Clean Air Through Transportation - Challenges in Meeting National Air Quality Standards

Click HERE for graphic. TABLE OF CONTENTS PageI. INTRODUCTION 1 A. Purpose and Scope of Report - The Provisions of Section 108(f)(3) 1 B. Summary 1 C. Background - CAA and ISTEA 8II. CHALLENGES IN TRANSPORTATION AND AIR QUALITY PROGRAMS 13 A. MPOs Face Significant Challenges in Meeting New CAA Requirements 13 B. Reducing Vehicle Emissions Through TCMs is Difficult 16 C. By Themselves, Capital-Intensive Investments May Not Be the Best Way to Address Air Quality Concerns 20 D. Technological Improvements Have Reduced Vehicle Emissions Despite Increasing VMT 29 E. Better Data and Models Are Needed 34 F. Beyond Transportation - Land Use, Public Acceptance, and Fiscal Constraints Figure Prominently 39III. STATUS OF PROGRAMS 43 A. Full Funding of ISTEA Would Help Meet Mobility and AirQuality Goals 43 B. Limited CAA Funds Exist for Air Quality Operations and Management 47 C. Regulations and Guidance Implementing CAA and ISTEA Have Been Issued 48 D. SIP Development, Revisions, and EPA Approvals Are Proceeding 56 E. Transportation Plans, TIPs, and Conformity Determinations Are Also Proceeding 59IV. CONCLUSIONS 63APPENDICESI INTRODUCTIONA. Purpose and Scope of Report - The Provisions of Section 108(f)(3)Section 108(f)(3) of the Clean Air Act as amended in 1990 requires theSecretary of Transportation (DOT) and the Administrator of theEnvironmental Protection Agency (EPA) to submit to Congress by January1, 1993, and every 3 years thereafter, a report that: "reviews andanalyzes existing State and local air quality-related transportationprograms...." The report is also required to evaluate the adequacy offunding and make recommendations regarding meeting the Act'srequirements. (See Appendix A for the complete text ofSection 108(f)(3)).This report is the first in that series. It provides the Congresswith: an identification of the challenges faced in attempting toimprove air quality through transportation projects and programs(Chapter II), the status of implementing the new transportationprovisions of CAA and air quality provisions of the Intermodal SurfaceTransportation Efficiency Act (ISTEA) (Chapter III), and conclusionsand recommendations (Chapter IV). This report generally covers the 2-year timeframe beginning with the promulgation of the 1990 CAAamendments, November 1990, through the end of fiscal year (FY) 1992.In many ways, it is too early to address whether the legislatedfunding and approach will be successful in meeting the goals of CAA. Federal guidance and regulations continue to be developed, and moststates and local areas around the country are just beginning todevelop and implement transportation plans, projects, and programs tomeet their CAA requirements. This report describes the challenges ofmeeting the requirements; future reports will be more comprehensiveand address the relative success of meeting CAA goals throughtransportation programs.B. SummaryMany areas that currently fail to meet the national ambient airquality standards, as well as the transportation and air qualityagencies assisting them, face formidable challenges if they are tomeet the CAA requirements. When they were enacted on November 15,1990, the 1990 CAA amendments set strict deadlines for these"nonattainment" areas to meet the standards depending on the severityof their air pollution problems for specific pollutants. The mostimportant pollutants for this report are ozone, carbon monoxide (CO),and particulate matter of under 10 microns in size (PM-10) wheremobile sources have a significant impact. The areas with the leastserious problems must reach attainment this year (1993); the mostsevere area, the counties around and including Los Angeles, have until2010.Click HERE for graphic.Nonattainment areas must reduce emissions that either directly causeor combine to form pollution from three primary sources: stationary,"area" (such as dry cleaning establishments), or mobile. A great dealof attention has been focused on mobile sources generally, and therole that transportation facilities (roads, transit, bike-, andpathways) play specifically, in part, because of the emphasis CAAplaces on transportation measures as a means to reduce emissions. Mobile source emissions can be significant; for urban areas they arevariously estimated at 40 to 50 percent for hydrocarbons (HC), whichcombine with oxides of nitrogen (NOx) to form ozone, 50 percent forNOx, and 80 to 90 percent for CO, and they can be higher in someareas. Reliable estimates for PM-10 do not yet exist, but total PM-10emissions are increasing.As the effort to meet CAA requirements for transportation-relatedpollution was undertaken across the country, distinct challengesbecame evident, and to place these challenges in context, severalpoints bear mention. Technological improvements have reduced emissions from motor vehicles despite increases in vehicle travel.Air quality, as measured in terms of CO, hydrocarbons and NOxemissions, has substantially improved over the last 10 years. Between1982 and 1991, total emissions from all sources have decreasedsubstantially (32 percent for CO, 13 percent for hydrocarbons, and 8percent for NOx), almost entirely from motor vehicles. But theimprovements have not been uniform from all sources. Stationarysource emissions, for example, have actually increased for certainemissions over the last 10 years. By contrast, motor vehicleemissions have generally declined between 1982 and 1991 due toimproved automobile technology, despite continued increases in vehicletravel. According to EPA's report titled, "National Air Quality andEmissions Trends - 1991," CO from mobile sources (highway, transit,and off-road engines) has decreased by 40 percent; NOx decreased by 25percent; and volatile organic hydrocarbons decreased by 39 percent(see Figures 1 and 2). Highway-related emissions showed even greaterreductions. Automobile travel has increased substantially. For example, between1983 and 1990, vehicle miles traveled (VMT) increased by 41 percent,continuing a century-long trend. A variety of trends contributed tothis growth: increases in the number of workers, increases in vehicleownership, longer average trip lengths, growth in suburb to suburbtravel, and continued decreases in the cost of driving. The real costof gasoline, for example, is now lower than it was in 1950. Effortsto reduce travel in single occupant vehicles and VMT face tremendouschallenges in light of these trends. Reductions from all sources will need to be considered in developing astrategy to meet the national ambient air quality standards. Inaddition to stationary and motor vehicle sources, area sources cancontribute a third or more to emissions in nonattainment areas. Aspecific type of area emissions, nonroad engines can contributebetween 7 and 17 percent of an area's hydrocarbon, NOx and COemissions, and in the struggle to reduce all emissions, new standardsmay be established for this increasingly important source. Nonroademissions come from a variety of sources ranging from agriculture andconstruction machinery to lawn mowers and garden equipment, and torecreational vehicles, including pleasure boats.While further reductions will be necessary from all sources, the costsand benefits of specific air quality strategies must be carefullyweighed to ensure that the most cost-effective strategies are selectedfrom among all sources of emissions. Federal funding available for TCMs has increased dramatically-- but most transportation control measures (TCMs) produce small emission reductions.The experience to date indicates that efforts to reduce emissionsthrough traditional TCMs have not generated significant air qualitybenefits. (See Appendix E for a description of traditional TCMs asdefined by section 108 (f) of CAA). Previously the lack of funds atthe local level to develop and implement competitive alternatives toautomobile travel was seen as a major impediment to reducing mobilesource emissions. This was addressed by ISTEA. Authorized at $155billion, ISTEA represents a significant shift in the waytransportation funds are used nationwide. It expands planning andresearch funds, establishes a new program, the Congestion Mitigationand Air Quality Improvement (CMAQ) Program to improve air quality, andenhances the flexibility that state and local governments have inusing other Federal funds. However, even with this funding increase,traditional measures are expected to have limited benefits.Low densities and high travel demand in suburban areas, low automobileuser costs, and an increasing number of trips generated by an eclecticAmerican lifestyle lead to relatively low participation rates inalternative forms of travel to the automobile. While transit is acrucial component of the Washington, D.C., transportation network, forexample, it carries only 13 percent of regional commuter trips. Andas a percentage of total regional travel, transit's share is evenlower. Making matters worse, the percentage of travelers using higheroccupancy forms of travel (transit, ride sharing) has declinednationwide, and single-occupant automobile travel has increased since1983. Across the country, the share of commuting trips made bydriving alone increased from 64.4 percent of all trips in 1980 to 73.3percent in 1990. Average vehicle occupancy decreased by 16 percentsince 1977.Recent modeling by MPOs shows that combinations of congestionreduction measures, including highway capacity expansion, andimprovements to ridesharing programs, transit and other TCMs produceonly 1 to 2 percent reductions in emissions without concomitant travelreduction efforts such as increased travel costs or restrictions andpolicies to increase land use density. Despite an $11 billion packageof transportation initiatives in the San Francisco area, for example,emissions are expected to decline by less than 1 percent compared tosimply maintaining current facilities and services.More effective measures exist, including pricing and other incentivesto stop driving alone, but these are politically unpopular and areuncharted territory in most urban areas. Other control measures thattarget emissions from every trip, such as inspection and maintenanceprograms, are likely to be more productive ways of making significantemission reductions. Measures that target the vehicles havingdisproportionately high emissions may also be effective. The modelling tools and technical information available to States and metropolitan planning organizations (MPOs) are imperfect.Within this overall framework, other challenges also face thetransportation and air quality community that arise from the dramaticchanges brought about by CAA and ISTEA. One challenge is caused bythe complexity of analyzing the effects of atmospheric changes andgeography on air quality and predicting the impacts of changes inhuman behavior on transportation and emission rates.Both the transportation and air quality communities have collecteddata and developed sophisticated tools for analyzing such effects,generally aided by computer models. But models to determinetransportation impacts on emissions have their shortcomings. Transportation models were not designed to develop emissionsestimates, and both transportation and emissions models rely onapproximations that only yield accurate predictions within certainparameters. Work is continuing in this area, but the lack of adequatedata and models poses a significant analytical challenge.Related to the need for better tools is the need for better technicalinformation. States and local areas must meet several requirementsthat necessitate high quality transportation/air quality information. They report that better data are needed on trends in travel demand,emission levels from cars and trucks in their areas, the effectivenessof technological improvements to reduce tailpipe and other emissions,and relative contributions from stationary, area, and mobile sourceinventories. Most importantly, states and local areas need betterinformation on what they can expect to achieve through TCMs. WhileFederal agencies have attempted to provide as much data as possible,better information can be developed only as better tools and morecomprehensive data become available. There has been a great need for guidance and direction, and Federal agencies have struggled to provide as much information as is available.Another need that has been often expressed by state and localofficials is for more, and more timely, guidance from Federalagencies. Enactment of two major pieces of legislation, CAA andISTEA, in a relatively short period of time has challenged EPA's andDOT's abilities to develop timely transportation/air quality guidance,but has also fostered a close working relationship between theagencies. The need to realistically address the requirements of theseActs has caused a convergence of purpose and precipitated a greaterunderstanding between them.DOT and EPA have provided detailed guidance in many areas. Substantial effort has been made to package and disseminate relevantinformation, jointly sponsor national conferences and regionalworkshops, develop coordination mechanisms through the NationalAssociation of Regional Councils (NARC), and respond to individualstate and local requests for information through site visits andtelephone communications. Guidance and regulations have beenpublished on VMT forecasting, transportation and air quality planning,state implementation plan development, motor vehicle inspection andmaintenance, the CMAQ Program, TCMs, and conformity.The conformity requirement bears special mention because itsignificantly changes the relationship between transportation and airquality agencies, and failure to meet it can bring transportationprograms and projects, both highway and transit, to a halt. UnderCAA, transportation plans and programs using Federal funds must"conform" to state plans to improve air quality, called StateImplementation Plans or SIPs. (See Section I.C.) If they fail tomeet the conformity test, projects contained therein cannot advance,with some exceptions. EPA and DOT jointly published interim guidanceon June 7, 1991, and EPA published a Notice of Proposed Rulemaking(NPRM) with DOT concurrence on January 11, 1993. The final rule isexpected in the fall of 1993. CAA and ISTEA have substantially increased the coordination requirements for transportation and air quality decisionmaking, entailing greater complexity and requiring more staff time.ISTEA and CAA not only changed the goals of transportation planningand implementation, they also altered state and localresponsibilities, and broadened the number of public agencies andprivate interest groups involved in the process. Local areas havebeen greatly empowered under ISTEA, and decisions over transportationpriorities are now the joint responsibility of local MPOs and states.With expanded responsibilities, many nonattainment areas discoveredthe need for more staff and better training. Almost 69 percent ofrecently-surveyed MPOs in nonattainment areas cited the need for morestaff to meet their obligations. Many had recently added staff. Approximately the same number said their personnel also requiredtraining in critical areas to develop effective transportationprograms to improve air quality. The most important areas wheretraining is needed were cited as: enhancement of technical skills,such as predicting the impacts of transportation programs (throughcomputer modeling, etc.), and enhancement of policy development skillsto manage interagency negotiations and consensus-building. Similarly,adequate staff and resources are concerns with other Federal, state,and local agencies concerned with transportation and air quality.With changing relationships and new partners in plan development, theneed for productive coordination has been greatly multiplied. Statetransportation and air quality agencies must work together with MPOsto meet their air quality needs. Air quality agencies mustsuccessfully collaborate in the development of transportationpriorities, just as transportation agencies must gain entree in theSIP development process. The traditional relationships that haveseparated these agencies must be reconstructed toward mutualunderstanding and cooperation. This pertains not only to state andlocal offices, but to Federal agencies as well.Similarly, as more community, citizen action, and private interestgroups have become involved in transportation plan development and thesetting of environmental priorities, they have brought new points ofview and new agendas, further changing the decisionmaking process. While such changes have greatly diversified the approach and added newperspective and information to the setting of transportationpriorities, they have also increased the potential for confrontation. Legal actions have already been threatened or initiated against statesas well as DOT. Managing the coordination process poses aconsiderable challenge and must be a high priority for agencies at alllevels of government.Finally, major budget shortfalls are common across the Nation. Manystates, localities, and metropolitan areas must focus their attentionand resources on many other real and pressing priorities, includingcrime, education, health care, homelessness, unemployment, andpoverty.C. Background - CAA and ISTEACAA and ISTEA provide complementary approaches to decreasetransportation-related emissions. CAA sets air quality requirementsand milestones, mandates further improvements to vehicles and fuels,requires greater integration of transportation and air qualityplanning procedures, and establishes penalties for failing to meet itsrequirements. The ISTEA provides funding and the flexibility to useit to improve air quality through development of a balancedtransportation program.CAA classifies nonattainment areas according to the severity of theirair quality problems. For ozone, these classifications in order ofincreasing severity are: marginal, moderate, serious, severe 1,severe 2, and extreme. For CO, they are: low moderate (<12.7 ppm),high moderate (>12.7 ppm), and serious. For PM-10, they are: moderate and serious. As the classification increases, so do thenumber of CAA-required actions the areas must take (see Appendices B,C, and D) and the time interval they have to meet the national ambientair quality standards (NAAQS). Depending on their classifications,some nonattainment areas will have to meet mobile source requirementsrelating to:o inspection and maintenance programs,o vapor recovery systems,o clean fuel fleet programs,o VMT limitations,o employer trip reduction programs,o reformulated gasoline, oro oxygenated fuels.All areas must determine and document the magnitude of the problem,set emission reduction targets, and specify the means by which thesetargets will be reached, including TCMs. TCMs are not generallymandated under CAA, but Employee Commute Option Programs--a TCM listedin Section 108(f)(1), are required in areas classified as severe andabove for ozone and serious for CO. These elements must be includedin the SIP. In addition, these areas must implement TCMs to offsetany growth in emission due to growth in VMT or vehicle trips. Under CAA, the SIP is the means by which a state monitors, controls,maintains, and enforces compliance with the NAAQS. The SIP isintended to set realistic numerical goals for each emissions sectorand enforceable measures to attain them, with input from thoseresponsible for development of emission reduction plans, as well asimplementation of those plans.Other plans and programs are also affected by CAA, specifically themetropolitan transportation plan and transportation improvementprogram (TIP). As noted above, CAA requires that the plans, programs,and projects contained in these transportation documents "conform" tothe purpose of the SIP. The conformity requirement significantlychanges the way transportation plans are developed in nonattainmentareas. In essence transportation plans and programs must ensure thatthe transportation sector contributes its planned share of emissionreductions. If they fail to do so, they must either be modified, orthe SIP must be modified to offset the disparity in projectedemissions, or they cannot advance. What this means is that iftransportation plans and programs fail to meet the conformityrequirements, they must be amended before they can be implemented. With some exceptions, this provision can hold up virtually the entireFederal highway and transit program until conformity is demonstrated.Generally, if a nonattainment area fails to meet its deadline forattaining the standards, it is automatically bumped up into the nextworse category. For example, all nonattainment areas designated asmarginal for ozone must either meet CAA requirements for attainment byNovember of this year or they will be redesignated as moderate areas.If a nonattainment area fails to meet the SIP submittal requirements,EPA must apply sanctions to DOT's highway program or sanctions thatrequire a 2:1 offset for new major stationary source emissions. Highway sanctions entail the withholding of Federal highway funds,except those targeted for exempted safety or environmentallybeneficial projects, and can be applied for SIP deficiencies relatednot only to mobile sources but stationary sources as well. Undercertain conditions, EPA may extend the boundaries within which highwaysanctions are applied to include the entire state.Two-to-one emissions offsets are applied to new stationary sourceswhere each ton of emissions generated must be offset by a two-tonreduction through additional control measures on existing stationarysources. EPA must apply highway or offset sanctions after 18 monthsto areas for failure to submit a SIP or a portion of a SIP,disapproval of a SIP by EPA, failure to implement the provisions of anapproved SIP, or failure to meet any other provisions required by CAA. Six months after the imposition of highway or offset sanctions, EPAmust apply both if the requirements have not been met. EPA interpretsthe CAA to give it authority to apply sanctions earlier on a discretionary basisin order to ensure that CAA requirements are met.As CAA prescribes the goals and procedures for achieving the standardsin nonattainment areas, ISTEA provides funding for reducingtransportation-related emissions. Previously the lack of funds at thelocal level to develop and implement competitive alternatives toautomobile travel and the dedication of most Federal fuel tax revenueto highways were seen as major impediments to reducing motor vehicleemissions. This was addressed by ISTEA through establishment of theCMAQ Program and enhancing the flexibility that state and localgovernments have in using Federal funds.Rather than narrowly categorized programs for highways, mass transit,and other forms of transportation, recipients can now use broadlyflexible funds, for a variety of transportation purposes. The largestprogram under ISTEA is the Surface Transportation Program (STP),authorized at $23.9 billion over a 6-year period. STP funds can beused at the discretion of state and local officials for many differenttypes of transportation programs, including highways, transit, TCMs,and planning and research. Further, ISTEA allows for transfers fromnational highway system, bridge, and interstate maintenance programsto STP, greatly increasing the flexibility with which many Federalprogram funds are used. Click HERE for graphic.Authorized at $6 billion over 6 years, the CMAQ Program directly fundstransportation projects to improve air quality and providesnonattainment areas with necessary resources to reduce congestion andprovide or improve alternative forms of travel, including transit,ridesharing, bicycling, and even walking. ISTEA precludes CMAQfunding for certain TCMs listed in CAA, specifically programs toreduce extreme cold start emissions and vehicle scrappage programs,despite emission reduction potential of such measures at least in theshort run. About $340 million of an authorized $809 million wasobligated in FY 1992, and well over half of this (58 percent) was usedfor transit. While the FY 1992 obligation rate for this program waslow by DOT standards at 42 percent, it is appropriate thatnonattainment areas carefully consider how best to spend these funds. Other typical projects under the Program included development ofhighway and road projects such as high-occupancy vehicle lanes,traffic signalization and incident management, and establishment of astatewide coordinator for bicycle and pedestrian transportation,ridesharing programs, and park-and-ride lots.II. CHALLENGES IN TRANSPORTATION ANDAIR QUALITY PROGRAMSA. MPOs Face Significant Challenges in Meeting New CAA RequirementsISTEA significantly increased the responsibility of MPOs in thedevelopment of transportation and air quality planning andprogramming. Their traditional transportation planningresponsibilities have been increased to include expanded roles inprogram and project selection. Because of these addedresponsibilities, some have questioned the current ability of the MPOsto evaluate and implement transportation control measures andeffectively advance these plans as part of the overall politicalprocess.In an effort to identify MPO concerns, NARC, the American Associationof State Highway and Transportation Officials (AASHTO), and theUniversity of North Carolina-Charlotte (UNCC) conducted surveys ofMPOs, and the Federal Highway Administration (FHWA) surveyed its fieldoffices. These surveys were aimed at determining what issues are ofmost concern to MPOs, and to identify ways in which the FederalGovernment can assist MPOs in implementing the air qualityrequirements embodied in ISTEA and CAA. Results of the surveys wereincorporated into a DOT effort, in coordination with EPA, to developan action plan that could be used to assist MPOs in carrying out theirnew transportation and air quality planning responsibilities. Whatfollows is a general compilation of specific issues that wereidentified as being areas of concern that are crucial to the MPOs'effective implementation of the transportation and air qualityrequirements embodied in the two acts.1. Staffing and TrainingGiven the fundamental changes in the nature and responsibilitiesfacing MPOs and states involved in the planning process, it isappropriate to consider whether their professional staffing andtraining are sufficient to carry out their expanded roles andresponsibilities. Based on its 1992 survey, UNCC estimated that 18percent of MPO staff in nonattainment areas were working on CAAissues, and that as many as 50 percent of staff in severenonattainment areas were working on CAA issues. According to the NARCsurvey, nearly 70 percent of MPOs thought they needed greater staffingto carry out new responsibilities under both the ISTEA and CAA. Itshould be emphasized that staffing resources in these areas generallyhave been static or declining over the past several years due to aleveling off of Federal funds for transportation planning. Since MPOstaff commitments are directed by annual planning work programs set inadvance, new priorities in staffing and organization will take time toimplement.As might be expected, many MPOs think their staffs need substantialtraining to carry out the transportation planning and air qualitymandates established in the ISTEA and CAA. Again, since most MPOs hadlittle or no ongoing air quality planning responsibilities, developingstrong technical and policy competence will take time. Nearly 80percent of MPOs responding to AASHTO and NARC surveys said they coulddraw on staff and technical support from various state agencies in theshort run.In the near term, MPOs may be forced to shift staffing prioritiestowards their new ISTEA and CAA responsibilities at the expenses ofsome traditional functions. In addition, they are using availablestate technical support in lieu of in-house training for staff andfull integration of air quality software into their transportationmodeling capabilities. Although there is no requirement that MPOsperform all such tasks themselves, most appear to prefer having therequired technical capabilities more immediately available from in-house expertise.2. Data, Models, and Technical InformationThe results of the FHWA field scan, as well as the NARC, AASHTO, andUNCC surveys, document a widely perceived need for better informationand analytical tools for transportation controls measures. TCMs willbe under consideration in most nonattainment areas. Nevertheless, thedevelopment of political or technical consensus and support forcertain TCMs will be difficult because of their effects on travelalternatives and their cost, travel behavior, and the perceptions thatvarious parties bring with them to the deliberative process. TCMselection and implementation will require a clear understanding of theair quality benefits that can be achieved, as well as an examinationof other consequences. Hence, the need for better information andanalytical tools for TCMs.In the area of transportation planning models, there is an urgent needto raise the state-of-the-practice in many metropolitan areas, and aneed to create a new generation of transportation models which canbetter reflect the dynamics of travel decision processes. There alsois a wide disparity among MPOs relating to the timeliness of theirtravel demand data bases. There is a strong need to expand datacollection to improve accuracy in VMT tracking, real-time output fromthe Highway Performance Monitoring System (HPMS), and estimates ofmode split, vehicle occupancy, volume to capacity ratios, andcommercial vehicle activity.With regard to air quality models, there seems to be a desire amongMPOs to improve understanding of EPA's MOBILE5 emission model andEPA's regional air quality model, since their outputs are so criticalto transportation system decision tradeoffs.3. Institutional Coordination - State and Local AgenciesThe MPO planning responsibilities within metropolitan regions arefocused on development of TCMs, and making conformity determinationson TIPs and Transportation Plans. State DOTs and MPOs need to beinvolved in the development of SIPs and in monitoring local attainmentof national standards. However, there is little consistency among thestates in the coordination between transportation agencies (stateDOTs, MPOs, transit agencies, or local governments) and theSIP-developing agency. Of particular concern is the lack of MPO orstate DOT involvement in emission inventory and budget development inmany states. Some MPOs even report that they are not involved inproject and program development.It is not entirely clear to what extent MPOs have been excluded from aprocess that is well underway and to what extent the process itself isnot advancing as well as it should be. Since MPO and DOT commitmentsto TCMs in approved SIPs will eventually be required, and sinceconsistency between the transportation plan and the SIP is necessaryto meet CAA's requirements for enforceability and adequate measuresfor implementation (at the time of SIP approval), it is important thatDOTs and MPOs be involved.Another area of varied MPO responsibility is that of growth managementand land use control. Traditionally, these functions have been theresponsibility of local governments. And while there is a growingbelief that land use and growth management can be important in thelong run to achieving transportation system efficiency, mobility, andreducing mobile source emissions, there is also a growing belief thatlocal governments acting individually do not achieve optimal regionalresults. Federal agencies must do everything possible to support anddisseminate research and information in this area to appropriatestate, regional, and local organizations.4. FundingThe NARC survey found that nearly half of the MPOs thought they neededgreater planning and research funds to fully implement their new airquality responsibilities. Nearly one-third responded that they have abacklog of transportation and air quality planning activities delayeddue to insufficient funding. Traffic monitoring and data collectionwere cited as areas specifically needing significantly increasedresources. In the case of TCM implementation, almost half of the MPOsbelieved increased funding would be needed to fully implement all TCMsplanned.Even though ISTEA substantially increased transportation fundinglevels and eliminated many of the restrictions on the use of Federalassistance, there remain many unmet transportation system needs. Forinstance, although STP and NHS funds may be used for planningactivities, there are many unfunded construction and operationsprojects competing for these limited resources, includingrehabilitation and reconstruction of aging transit and highwayinfrastructure, traffic signalization, congestion alleviation, andsafety needs.5. Public Awareness and Involvement ISTEA mandates an opportunity for strong public input and review oftransportation plans and programs. Further, the public, as well asstate and local elected officials need, to understand the CAArequirements, the benefits of reduced emissions, and the effectivenessof various measures to achieve those benefits.Even though ISTEA will result in substantially-expanded publicparticipation in state and MPO planning and programming processes,achievement of general public consensus will be difficult. In thecase of air quality, the public will undoubtedly demand to know thatincreasing its transportation costs or reducing mobility will resultin cleaner air. Also those who perceive themselves to be adverselyaffected by transportation infrastructure projects in any way willvery likely raise air quality issues. The expanded public involvementcan be expected to assist elected officials in understanding thenature of impacts associated with their decisions. It will alsorequire a full knowledge of the implications of their proposed actionson the part of staff as well as decisionmakers.B. Reducing Vehicle Emissions Through TCMs is DifficultDespite the significant emission reductions that have been achieved,many areas of the United States have not attained the NAAQS for one ormore specific pollutants. While nonattainment areas have gleanedemission reductions from technological controls of stationary andmobile sources, many of them must now consider additional strategiesfor emission reductions necessary to attain the NAAQS. TCMs are beingconsidered as part of those strategies. TCMs must be part of abalanced transportation plan that meets both air quality and mobilityobjectives. However, based on preliminary indications, thetraditional methods of altering transportation behavior by offeringalternatives have not yet been shown to significantly reduceemissions.TCMs are intended to decrease mobile source emissions by eliminatingor reducing motor vehicle trips, cold start emissions, VMT, andhighway congestion. And they are usually meant to affect individualbehavior by inducing transportation mode shifts or shifting travel tooff-peak times, which can result in a decrease in mobile sourceemissions.Certain TCMs are listed in Section 108(f)(1) of CAA and, with twoexceptions, identified as eligible strategies under the SurfaceTransportation and CMAQ Programs of ISTEA. The CAA list offers asample of the traditional control measures available to state andlocal governments which includes improved public transit, developmentof bicycle and pedestrian facilities, trip reduction ordinances,vehicle access restrictions, and traffic flow improvements, amongothers. Of the Section 108(f)(1) TCMs, only the employer-basedtransportation management plans (employer trip reduction/employeecommute options) are specifically required and then only in Severe andExtreme ozone- and Serious CO nonattainment areas.Despite the emphasis placed on these TCMs, it will probably benecessary for many state and local governments to look beyond theseTCMs in order to attain the ozone and CO NAAQS. In particular, TCMsthat focus on providing more attractive alternatives to SOV travel arelimited in effectiveness. (See also Chapter II.C.) Preliminaryindications from around the country indicate that traditional TCMswill yield only a 1 to 2-percent reduction in mobile source emissions,far short of what some areas will need.Historically, decreasing emissions from mobile sources mean that TCMswill incur emission reductions off a shrinking base, at least for HCand CO. More generally, the transportation sector's ability tocontribute to regional emission reductions shrinks with its portion oftotal regional emissions. In many areas these trends will continueresulting in smaller and smaller TCM impacts on regional emissions. In other areas, continuing increases in travel could lead to anincreasing share of total emissions by the transportation sector. Here, the types of TCMs employed will be critical--are they trip-based, VMT-based, from work trips--and will determine theeffectiveness of different kinds of emission reduction strategies.Substantial changes in the level of TCM effectiveness will require alllevels of government to look beyond traditional TCMs toeconomic/market-based TCMs, such as congestion pricing, increases inparking prices, emissions charges, etc., which show greater emissionreduction potential. The introduction of economic/market-based TCMsinto the transportation supply and demand decision making process canand must be designed to improve mobility and air quality, and at thesame time not detract from regional economic growth. Regulatory TCMs included in Section 108(f)(1) and others which placerestrictions on automobile travel show greater emission reductionpotential than TCMs that increase the supply of transportationalternatives. But economic/market based TCMs have some importantadvantages as emission-reduction strategies over strictly regulatoryTCMs. For example, economic/market-based TCMs can apply to all typesof drivers and all kinds of trips - not just employment-relatedtravel, as employer trip reduction programs are structured. In thatworktrips only constitute 26 percent of all trips, almost three timesmore trips are unaffected by TCMs targeting commuting trips.While providing a disincentive to SOV travel, economic/market-basedTCMs can alter travel behavior, and at the same time, maintainindividual choice concerning travel mode. For necessary work- orother-related travel, absolute restrictions are not imposed, and thosewho would be burdened the most by abandoning their cars, e.g., peoplewho rely on their cars for business, need not do so. Perhaps thegreatest advantage of economic/market-based TCMs over traditional TCMsis that economic/market based TCMs can enhance ridership onconventional travel alternatives--rail, bus, carpooling--and offerindividuals and businesses the incentive to develop innovative optionssuch as telecommuting and vanpools. Other advantages can includegreater economic efficiency and reduced congestion.VMT/emissions pricing is one method that uses economic/market-basedincentives to bring about behavioral changes many traditional TCMsfail to achieve. A tax on VMT/emissions can theoretically provide asignificant incentive to drive less and use cleaner vehicles. Congestion/road pricing is another way which uses market disincentivespotentially providing benefits that traditional TCMs cannot. It canbe argued, for example, that road/congestion pricing is more effectiveand fair when compared to indirect pricings such as fuel orregistration fees because road pricing can be tailored to thelocation, level and duration of traffic congestion or emissionproblems. In addition, the external and unaccounted costs of driving-- pollution, congestion, accidents--which vary with driving conditionsand have the highest impacts during congested periods on specificroadways, may be accounted for in some congestion/road pricing plans.A pricing strategy need not, however, begin by charging for theseexternalities. Charging users the full cost of road construction andmaintenance on local roads, for example, could constitute anefficacious incentive and produce revenues which might then be used tolower taxes or increase other services. A broad based pricingmechanism such as this is likely to be more effective since it targetsall trips and not just work trips.Despite these advantages, economic/market-based mechanisms must beimplemented carefully to ensure equity and to realize the air qualitybenefits. For example, raising the costs of SOV travel could havedisproportionate impacts on the working poor. Where such impactsoccur, mitigation measures such as tax rebates, transportationvouchers, or new cost-effective transportation alternatives can offsetthem and should be considered. (It should be noted, though, that manycurrent transportation costs and benefits are also not distributedequally). Moving to a system which charges those who benefit islikely to improve the fairness of the transportation system byshifting costs to those who create them. In any case, a moreefficient use of infrastructure would decrease transportation-relatedcosts and externalities generally.Other implementation issues are also important. Most pricingmechanisms need to be implemented uniformly throughout a nonattainmentarea or SOV travelers will be able to find and use alternate roads,parking and other facilities to avoid the higher costs, causingproblems in other areas. Finally, such mechanisms require strongpolitical will to be implemented. Recent experience has shown thatmany consumers balk at the notion of higher fees and taxes without aclear understanding of the benefits. All levels of government willneed to support an economic/market-based approach if it is to assistin reducing emissions, maintain mobility, and gain public acceptance.While an individual TCM may only provide a small emissions reduction,a grouping of selected TCMs which includes economic/market-based TCMscould yield greater emissions reductions. Accordingly, complementaryTCMs should be developed and evaluated as part of a coordinatedstrategy with particular attention on intermodal alternatives.Although TCMs can assist in reducing emissions, the level of theireffectiveness varies across the country because of geographic,meteorological, demographic, and economic differences. Therefore,neither DOT nor EPA can assign uniform effectiveness values to eitherindividual TCMs or groups of TCMs. Furthermore, the state-of-practiceand data on which to conduct analyses are inadequately developed inmany areas to assess all TCMs which may be of interest.While the ability to evaluate a TCM's effectiveness for reducingmobile source emissions is not an exact science, EPA has individually,and jointly with DOT, undertaken several projects aimed at increasingthe accuracy and amount of information concerning TCMs. (See ChapterIII.C.) In addition, EPA is currently preparing guidance onmethodologies for estimating emissions and travel activity effects ofTCMs. EPA has provided a grant to the University of Michigan to doresearch on human behavioral characteristics as they relate totransportation choices.These projects, although beneficial, will probably not producedefinitive information needed to accurately estimate the emissionsreduction benefits directly attributable to TCMs in all cases. Additional research into the emission reduction potential of TCMs iswarranted. The combination of market disincentives to SOV use coupledwith attractive alternatives should be pursued, including theirpotential costs and benefits. Finally, every effort must be made toshare relevant information among Federal, state, and local agenciesand raise the state-of-practice in areas where it is needed.C. By Themselves, Capital-Intensive Investments May Not Be the Best Way to Address Air Quality ConcernsAn important question in developing transportation/air qualityprojects and programs is how to best use Federal and other funding. Some TCMs require large capital investments and a great deal of fundsin new or expanded high occupancy vehicle (HOV) lanes, transit, orintermodal facilities. Others may be of relatively low capitalintensity such as pricing and regulatory mechanisms or ridesharing. Of course, many TCMs will fall between these extremes, and differentnonattainment areas will undoubtedly use the increased funding underISTEA to finance a wide variety of projects to address theirtransportation and air quality needs. It will be important for eacharea to decide among the capital alternatives based on the relativecosts and benefits, but there is little evidence that capitalinvestments in new transportation facilities, particularly largeinvestments, are the best way to improve air quality. In fact,available information and analysis suggest that capital investmentswhen made without disincentives to SOV use have negligible impacts onair quality.Information to judge the effectiveness of different transportationinvestments or control strategies in reducing emissions is limited. This is partly because the emissions consequences of transportationcapital projects are difficult to evaluate systematically andvirtually impossible to actually measure in isolation from otherinfluences. Most analyses of the effectiveness of capital investmentsand TCMs are based on simulations using regional transportation andvehicle emissions models rather than on the measured impacts of actualprojects or controls. These models usually have at least somestructural or conceptual simplifications which leave room for doubtabout the accuracy of their predictions.Nevertheless, useful estimates of the potential effectiveness of newinvestment as an emissions-reducing strategy can be inferred. And theevidence suggests that capital investments in transportationfacilities are not likely to produce significant emission reductionsby themselves, although they may be more effective when undertaken inconjunction with pricing or regulatory mechanisms to reduce SOVtravel. 1. Evidence from CaliforniaBecause of the severity of the air quality problems in California, TCMeffectiveness has been the subject of considerable analysis there. This section reports on four studies that show the relatively lowemission benefits of capital-intensive TCMs. In one study done byHarvey on the 1991 Clean Air Plan for the San Francisco Bay area, over22 TCMs were evaluated. Of these, the market-based mechanisms (smogfees, congestion pricing, gas taxes and increased parking charges)showed the greatest air quality, reducing mobile source emissions fromabout 4.5 to 7.6 percent. In comparison, the capital-intensive TCMswere much less effective. For example, an expansion of the regionalrail system, including an extension of the Bay Area Rapid Transit(five stations) and the Tasman light rail (12 miles), would reduce HCand CO by only 0.86 percent each. Similarly, adding 300 miles of HOVlanes to the existing network would reduce HC and CO by only 0.64 and0.62 percent, respectively. Table 1 reports the results from two other analyses that attempt topredict the emission reductions from transportation controls andrelated programs. These estimates are drawn from a variety of sourceswith varying degrees of precision, tend to be optimistic, and need tobe interpreted cautiously. Nevertheless, the table supports the ideathat only small emission reductions will result from TCMs generallyand further indicates that high-capital TCMs are not expected to beamong the most effective in reducing emissions.The statistics from Los Angeles are based on the Air QualityManagement Plan (July 1991 update) developed by the South Coast AirQuality Management District (AQMD). It offers emission reductiongoals that would be necessary to bring Los Angeles into compliance bythe year 2010. The total cost of such measures is difficult toestimate, but the direct costs of the transportation investmentsneeded to meet these goals is projected to be $5.16 billion per yearuntil 2010. The emission reduction goals estimated by Los Angeles areconsiderably larger than the projections by San Diego. According toMPO personnel, whether they can achieve such targets remains to beseen.The analysis done for San Diego was an effort sponsored by CALTRANS todetermine the effectiveness of potential TCMs that could beimplemented to meet the NAAQS. The TCM costs and the time needed toimplement the selected TCMs were not provided in the analysis butwould be considerable for many of them, especially those targetingland use management, and transit expansions.For both San Diego and Los Angeles, the most capital-intensiveinvestments resulted in the smallest percentage decreases inemissions. For example, a 20-mile extension of San Diego's light railline is expected to reduce HC and CO emissions (from mobile sources)by less than 0.4 percent and 0.6 percent, respectively. Similarly,construction of an extensive rail transit system in southernCalifornia is expected to reduce HC emissions by about 1 percent andCO emissions by 3 percent, even in conjunction with areawide adoptionof measures to encourage its use.Another study by the Metropolitan Transportation Commission, SanFrancisco's MPO, showed that an $11 billion investment intransportation initiatives will yield a 0.9 percent and 0.8 percentreduction in CO and HC emissions, respectively. San Francisco'sinvestments were primarily comprised of new transit lines, HOV lanes,and local arterial improvements. The analysis showed littledifference between large mass transit and large highway projects.The low projected emission reduction is unsurprising. San Franciscoand many other nonattainment areas have massive transportationinfrastructures already in place. Further investment, even $11billion worth, only marginally changes the existing infrastructure andconsequently has a marginal impact on emissions as well.Control measures that generally have lower capital costs, such asincreased prices for parking and vehicle use, and telecommuting, areanticipated to be somewhat more effective. Such measures will likelyhave variable costs associated with them, ranging from net benefits tovery high compliance costs on firms or individuals. But, as suggestedabove, revenues generated by these mechanisms can be used to mitigatethe impacts on particular groups. In any case, these measures doappear to offer potential for greater emissions reductions. Table 1 Emission Reduction Targets For Selected TCMs (from Mobile Sources) SAN DIEGOClick HERE for graphic. LOS ANGELESClick HERE for graphic.Sources: 1. From Loudon and Dagang, "Predicting the Impact ofTransportation Control Measures on Travel Behavior and PollutantEmissions," JHK Associates, 1992. 2. South Coast Air Quality Management District, "AirQuality Management Plan," Appendix IV-G, 1989.2. Interim Conformity FindingsMost nonattainment areas have now been through two rounds oftransportation conformity determinations under CAA. Taken together,they indicate that transportation infrastructure programs alone willmake little difference in changing regionwide mobile source emissions. Further detail on what many areas included in their TIPs needs to beexplored. And while much is known about the extensive programs inCalifornia, other areas may not have incorporated programs toinfluence land use, TDM measures, or other more stringent efforts intheir TIPs. Further their analyses may not fully examine the impactincreasing congestion can have on travel behavior. Still, theprograms put forth so far show that expanded infrastructure will yieldless than a 2-percent emission reduction in most cases.By contrast, most nonattainment areas anticipate that even without newcapital investment, mobile source HC and CO emissions will decline by4-5 percent each year and in some areas considerably more, accordingto an analysis of the first round conformity determinations. But itshould be noted that realizing these estimated emission reductionswill depend on future VMT increases and that such reductions are notexpected for PM-10 emissions which are increasing. These reductionswill come primarily from newer vehicles with additional emissioncontrol features and from reductions in gasoline volatility, a majorcontributing factor to evaporative emissions.Under the Interim Conformity Determination procedures established byEPA and DOT, nonattainment areas are required to submit estimates offuture year emissions levels under two sets of conditions: first,assuming that no additions to their regional transportation networkswould be made (the "no-build" case); and second, assuming that allinfrastructure projects and TDM programs included in their RegionalTransportation Plans and/or TIPs were fully implemented (the "build"scenario). These estimates were required for both the milestone year(1995 or 1996) and for the horizon year, by which each area isexpected to comply with the NAAQS. (See Appendices B, C, and D for alist of deadlines by nonattainment status.) Since it is unlikely thatmany TDM measures were included so soon after passage of the 1990 CAAamendments, the "build" versus "no-build" comparison predominantlyserves to examine the impact of new transit and highwayinfrastructure.The anticipated differences in emissions levels between the "build"and "no-build" scenarios are quite modest. Anticipated reductions inHC emissions by the milestone year were greater than 2 percent in onlya few cases, and most nonattainment areas estimated a 0 to 1-percentdecrease. Similar, though somewhat larger, decreases were estimatedfor CO emissions. Still, in only a very small number of areas were COdecreases expected to be more than 5 percent. By the horizon year,considerably more nonattainment areas expected emission reductionsgreater than 2 percent, but well over half expected thatimplementation of their current TIPs would reduce emissions by lessthan that. While current analytical techniques preclude greaterprecision, it is clear that the impact of the measures included in thedeterminations is small.Among the tasks facing some MPOs and DOTs is the need to develop newand innovative approaches to reduce mobile sources and to insure thattheir modelling methods can predict the air quality impacts as well aspossible.3. Investments in New Rail Transit.Further evidence about the emissions reduction potential of oneimportant category of capital intensive TCM is the construction ofrail transit facilities. Rail transit is of particular interest dueto its high visibility and high cost, and due to the availability ofexamples in several areas. Despite the significant investment in railtransit, ridership increases that would significantly affect emissionslevels have not materialized. While rail projects in Washington,D.C., Atlanta, and Baltimore added significantly to transit ridership--67 percent, 18 percent, and 14 percent respectively--increases inother locations were very modest or failed to occur. Such increasesin ridership, however, are not reflective of concomitant emissionsreductions since the proportion of regional travel carried by transitis typically very small. In the Washington, D.C., metropolitan area,for example, transit's share of commuter trips is 13 percent, andWashington's Council of Governments in its "1982 Regional Air QualityPlan" estimated that Metrorail's impact on emissions from all tripscombined was about a 1-percent reduction.Analyses from the Boston metropolitan area also suggest the high costof emission reductions from new rail services. One study examined thecost-effectiveness of various alternatives including an expansion of asubway line (one station) and rehabilitation of the commuter rail line(four stations). The analysis shows that these transit investmentswere not cost-effective means of reducing emissions, with HCreductions costing $100,000 per ton when all costs were assigned to HCreduction. Others were far more productive. Even the addition of20,000 more park-and-ride spaces was somewhat more cost-effective,although this study did not consider the effects of policies overtime.Noninvestment transportation measures tend to be more cost-effectivebecause they affect the whole fleet, and the rate at which the fleetpollutes. According to the Boston study, inspection and maintenance(I/M) programs, for example, affect the entire fleet and yield greatercost-effectiveness, between $1,400 and $5,300 per ton. I/M programscan even be more cost-effective. According to recent EPA estimates,I/M programs could be as cost-effective as $500 per ton. This widevariation in control costs is not unique to transportation-relatedemissions; stationary source control costs also cover a wide range,from net savings to costs of $20,000 per ton.Further along the cost-effectiveness scale, reducing a travel subsidycan have net benefits. For example, over 95 percent of U.S. employeesreceive a tax-free parking subsidy at work. Offering them the cashvalue of that subsidy gives them a choice: continued subsidizedparking or cash. Such an approach was examined by Shoup in 1992 andshown to help people save money (by carpooling or walking withoutforcing them to do so), decrease a subsidy, and decrease emissions. Table 2 Cost-Effectiveness of HC Emission Control MeasuresClick HERE for graphic.Sources: "The Mass Transit Air Quality Link," Antonioli, 1992; and"Cashing Out Employer-Paid Parking," Shoup, 1992.One reason for the modest air quality effects attributed to new railtransit is that only part of the additional ridership of these systemsis drawn from SOV users. Others are drawn from buses, carpools, andlatent demand. In addition, many riders access rail stations byautomobile, meaning that their trips still entail engine cold startsand subsequent cooling down. This generates the bulk of HC emissions--65 percent from a 10-mile trip--because of an automobile's relativeinefficiency and higher emission rates while warming up and highergasoline evaporation rates when cooling down.Of course, this is not to say that existing rail services should beallowed to deteriorate or even that further investments should not bemade as part of a comprehensive strategy or for other reasons. Innortheastern cities with long-established rail transit systems, thereis little doubt these urbanized areas would suffer much worsecongestion and air pollution if these rail systems ceased operating. In the greater New York metropolitan area, for example, there isvirtually no alternative to a viable rail system. Subway ridership isover three million passengers per day, and this does not includepatronage from two of the largest commuter rail systems in thecountry. No combination of automobile travel and other transportationalternatives could accommodate this level of demand for theforeseeable future. It should also be noted that new rail systems andextensions are justified on the basis of fulfilling a range ofobjectives besides air quality improvement: improved accessibilityand travel time, reinforcement of desired land use patterns anddensities, energy considerations, etc. When viewed in this broadercontext, the very modest air quality effects are seen as ancillarybenefits of these systems, not the primary reason for implementingthem.Experience with bringing new rail systems on line over the past 20years has shown that they cannot approach their carrying capacityunless accompanied by measures that would allow transit to competemore effectively with SOVs. The experience in Washington, D.C., overthe past decade is a case in point. There, despite having a fairlybuilt-out rapid transit system and land use controls that aregenerally supportive of transit use, the system was not able toincrease its share of journey-to-work trips throughout the region. From 1980 to 1990, the Washington Metrorail system grew from 30 to 73miles of line and opened an additional 30 stations. And the number ofworkers using rail transit grew from 69,000 to 143,000, a significantincrease. However, the number of people driving alone to work in theWashington metropolitan area also increased dramatically from 980,000to 1,394,000, and overall transit's mode share declined slightly. Thesituation in Washington with respect to personal travel trends ismirrored in other urban areas as well. To the extent that costly newrail projects are relied on as transportation control measures toimprove air quality, it is clear that their effectiveness dependslargely on a comprehensive, regionwide program that makes transit amore attractive option relative to single-occupant driving.4. Supply of Alternatives versus Demand for SOV TravelEven if capital investment in transportation is not the most effectiveemissions-reduction strategy taken alone, it may still represent animportant complement to other measures. Capital investments in newHOV facilities, expanded transit service, or widespread facilities for exclusive use by bicyclists and pedestrians increase the supplyand attractiveness of transportation alternatives to SOV travel.For such TCMs to be effective at reducing emissions, however, largenumbers of trips must be shifted from SOV to non-SOV travelalternatives, and experience has shown that increases in supply alonewill not produce these shifts. In addition to increasing the supplyof non-SOV options, the demand for SOV travel needs to be reduced. Inmany cases, high demand for SOV travel is a direct result of freeparking and other distortions in the transportation marketplace, andsuccessful demand management can reduce those distortions. Travelersact to minimize a combination of time and money costs, and thuseliminating subsidies has shown significant effects. The simple actof charging for, rather than giving away, parking has shown 20-45percent decreases in SOV commuting rates for individual employers(Shoup 1992), although similar regional impacts have not yet beenshown. This is even true in poorly transit-served areas of suburbanLos Angeles.TCMs that increase the cost of commercial parking, reduce or offer acashing out of employer-provided parking, establish road andcongestion pricing mechanisms or VMT restrictions can be effectivemeans of reducing the demand for SOV travel. Such measures willimpose variable costs which can be quite high. For understandablereasons, such measures are unpopular with those bearing the directcosts when they are.Some people argue for simultaneously increasing the supply andattractiveness of alternatives through capital investments andcreating disincentives to SOV travel as a way to create an integratedprogram that maximizes emission reductions. Such a program will noteliminate resistance to SOV disincentives but may reduce it becausethe program includes more visible and widely supported elements, suchas capital investments in transit, ridesharing, bikeways, and othertransportation alternatives and critical elements necessary to achieveemission reduction targets. Others argue that all too often theattractive and sometimes costly TCMs are offered without the tougherdisincentives to SOV travel.Resistance to SOV disincentives has varied but can be significant. InWashington, D.C., and many areas around the country, major politicalbattles have been fought over the implementation of parking or roadwayrestrictions. In the Nation's capital, the opposition has comedespite major investments in bus and rail transit and 2 major HOVcorridors. A more encouraging example comes from Portland, OR, whichover the past 20 years has removed a major freeway, canceledconstruction of another, imposed a parking moratorium, and passedtransit-supportive zoning changes and bond initiatives, all withsignificant public support. Yet even the Oregon Legislature declinedto take the next step to implement congestion pricing and vehicleemission fees, as recommended by a special state task force.5. Long-Term Emissions Consequences of Capital InvestmentWhile the short- to midterm emissions impacts of transportationcapital investments are modest, their longer term effects may be morepronounced. Because of their durability, these investments continueto influence urban travel patterns over a prolonged period and in turnhave an impact on the location of homes and businesses. Householdsand businesses base their location decisions in part on theaccessibility and convenience provided by the regional transportationnetwork. As transportation investments are made, certain locationsare made more desirable which, as new businesses and residencesrelocate, increases utilization of the transportation facility. Ofcourse other variables, such as building costs, crime, schools, andother amenities, also play a significant role in household andbusiness location decisions. (See Chapter II.F for more information.)Certain types of investments may decrease emissions over time. Thebenefits of this longer term strategy, however, may not be realized intime to assist nonattainment areas meet the NAAQS according to thedeadlines set out in CAA. The first deadlines occur this year andmost areas are supposed to reach attainment before the year 2000. Even the Los Angeles area only has until 2010 to meet the standards. These are relatively short timeframes to effect such land use changes.In summary, if large reductions in vehicle travel are sought, State-and locally-elected officials will need the political will to maketough decisions necessary to adopt and implement the kinds of TCMs,such as stringent and economically viable pricing mechanisms, thatwill reduce the attractiveness of SOVs in their region, yet preservemobility. Previous emphasis has been on reducing commuter travel, andstrategies that affect every trip - commuter and nonwork - will benecessary if significant emission reductions are to be realized.D. Technological Improvements Have Reduced Vehicle Emissions Despite Increasing VMTThe CAA provisions intended to reduce SOV travel and VMT posetremendous challenges for transportation, air quality and land useplanners, particularly in light of the travel trends in the UnitedStates. Efforts to control VMT have mostly concentrated oneliminating work trips, but given the rising importance of other trippurposes, such efforts are destined to be marginally effective alone. Efforts to control total VMT require broad support to pass enablingstate legislation, making them beyond the jurisdiction of thetransportation and air quality communities. Other ways exist toreduce highway emissions, such as inspection and maintenance programsand other programs targeted at so-called "gross-emitters." 1. Transportation TrendsVehicle travel is by far the predominant travel mode in the country. Of 250 million daily passenger trips, 94 percent are made inautomobiles or trucks and only 2 percent by public transportation. Automobile travel as measured by VMT has increased markedly, faroutpacing population growth and household formation in the recentpast. Between 1983-1990, passenger VMT increased by 41 percent,compared to relatively slight increases in population and households(6 and 9 percent, respectively).Click HERE for graphic.The reasons for increased VMT are varied. The 1990 National PersonalTransportation Survey identified several major national trends intravel patterns that offer a partial explanation. First, there hasbeen a dramatic increase in the number of workers, particularly women,up 58 percent since 1969 which means an increase in commuter travel. Second is an increase in the number of jobs located in the suburbswhere generally fewer travel alternatives are offered and distancesare greater than suburb-to-city travel. Suburb-to-suburb travel isnow the dominant commuting pattern in the United States. Third,vehicle ownership has increased significantly between 1969 and 1990. Nationwide, households with two or more vehicles increased from 31percent to 58 percent. And finally, average automobile occupancycontinued to decline to 1.5 in 1990, from 1.9 in 1977. Vehicleoccupancy for work trips is even lower and dropped under 1.1 personsper vehicle in the last 10 years.The cost of gasoline has also been a significant factor in VMT growth. Gasoline costs in real terms are now lower than they were in 1950. Fuel efficiency has also increased dramatically. Low fuel costscombined with high fuel efficiencies means that marginal per-miledriving costs are among the lowest they have ever been.While more people are driving more cars for more miles, highwaycapacity has been practically constant since 1970. Depicted in Figure 5, highwayroad-miles have increased slightly, 4 percent, since 1970, although itshould be noted that in urban areas capacity has increased moresignificantly. One consequence of this is clear--increasingcongestion. Furthermore, many have become concerned that these trendsmean worsened air quality.Click HERE for graphic.These data suggest the continued dominance of personal vehicles forpassenger travel. The large increases may slow as vehicle ownershipapproaches saturation and female participation in the work forcelevels off. Nevertheless, the multiple trends contributing to growthshow how difficult it will be to reduce traffic congestion and theresulting air pollution. This difficulty is reinforced by the currentland use patterns of dispersed residences and jobs, with thecorresponding heavy reliance on automobiles and limited alternatives.2. Control MechanismsBecause of the above trends, increasing attention has been focused onways of controlling VMT, with particularly emphasis on controllingwork trips. Work trips, however, have dropped to only 26 percent ofall trips, down from 32 percent in 1969. Similar trends aredemonstrated for purpose-specific VMT. So, if controlling VMT is anecessary and desirable way of reducing mobile source emissions,targeting work trips alone limits the overall effectiveness of thestrategy.As work trips decreased as a percentage of all trips, other trippurposes increased. The share of trips made on family or personalbusiness increased from 14 percent to 24 percent, for example, between1969 and 1990; shopping trips increased from 15 percent to 20 percentin the same period. Clearly if VMT is going to be effectivelycontrolled, trips for every purpose, not just journey to work, need tobe targeted.Effecting changes in travel behavior can be accomplished by adjustingthe comparative advantage each offers, particularly through thedisincentives discussed above, i.e., regulatory or market-basedinitiatives. Unlike providing new infrastructure or better services,such initiatives often require enabling legislation at the statelevel. Winning the public support necessary for enactment has shownto be extremely difficult. Enabling legislation requires not only theconsent but the active participation of elected officials. In thissense, such initiatives are substantially beyond the control of eitherair quality or transportation officials and the communities theyrepresent, and a much broader base of support is necessary toimplement them.Another means to control mobile source emissions is to target thosevehicles producing the greatest amount of emissions. Only 10 percentof all vehicles on the road produce between 50 to 60 percent ofhighway CO emissions. (Less dramatic impacts are demonstrated forother emissions: 10 percent of the vehicles produce 40-50 percent ofHC emissions and 20-30 percent of NOx emissions. These considerationsmay not apply to PM-10 in a significant way). Since such grossemitters are the predominant source of highway emissions and not onlyincrease the formation of CO hotspots but ambient pollution as well,reducing their impacts can effectively improve air quality withoutradically disrupting American economic and lifestyle choices.3. Emissions Consequences and Control Strategy ImplicationsClick HERE for graphic.Even as VMT increased, mobile source emissions declined as strictertailpipe measures were established and enforced. Since 1982,hydrocarbon, CO, and NOx all decreased by substantial margins;hydrocarbons are down 39 percent, CO decreased 40 percent and NOxdeclined 25 percent, according to the EPA report, "National AirQuality and Emissions Trends - 1991." Given the growth in VMT,however, the environmental and transportation communities areconcerned that rising VMT may eventually overtake the emissionimprovements realized over the last 10 years.Technology has improved the emission rates of new cars considerably. For example, 1990-model vehicles emit hydrocarbons and CO at only one-third the rate of 1975-model vehicles. In the near term, furtheremission reductions can be expected as older vehicles are retired andreplaced with newer, cleaner ones. But even with these technologicalimprovements, the total vehicle emissions could once again increase ifVMT rises rapidly. Some estimates predict that mobile sourceemissions will again rise on or about the year 2005. Others suggestthat VMT growth will subside and negative emissions impacts may beaverted.Whether and when emissions rise again with VMT (under uncontrolledconditions), and to what level, depends in part on what is done in thefuture to reduce the emissions per mile of travel. The 1990 Clean AirAct has resulted in the implementation of even stricter tailpipe andevaporative emission controls that will increasingly benefit all areasover the next two decades. Enhanced inspection and maintenanceprograms, now required in nonattainment areas designated serious andabove for ozone (or high moderate and above for CO), use hightechnology emissions testing on an annual or biennial basis along withsupplemental on-road emissions testing to insure that vehicles meetthe standards. If they do not, maintenance is required to bring theminto compliance. EPA estimates that enhanced I/M programs can yield a28-percent emission reduction. Areas not specifically required toadopt enhanced I/M can choose to do so for greater emissionsreductions and to reduce the need to control VMT. Similarly, statesand nonattainment areas variously must or may choose (depending onclassification) to implement other technology-oriented measures suchas reformulated gasoline, oxygenated gasoline, California vehiclestandards, clean fuel fleets, or other measures.Nevertheless, VMT reductions (uncontrolled) through control mechanismsdescribed earlier may be part of the preferred long-term strategy. The overall emissions control strategy that is right for an area willdepend on the overall emission reduction that is required, as well ason local preferences among all the control possibilities. To theextent that vehicle technology and fuel measures cause smaller per-mile emissions, they tend to shift the logical focus for additionalemission reductions away from VMT and on to trips and nonvehiclesources. It should be noted that in many areas, congestion reductionand quality of life are also reasons to consider many VMT controlstrategies.Except for fuel changes and inspection and maintenance programs, thetechnology measures' benefits will phase in gradually and will notprovide much of a contribution to meeting the requirement to reduceVOC emissions by 15 percent by 1996. Because growth in emissions fromrising VMT must also be offset in addition to the 15 percentreduction, the rate at which VMT will grow naturally is a crucialquestion to determine the importance of reductions from new efforts tolimit VMT growth, fuel changes, enhanced I/M, and non-vehicle controlmeasures. The affected states are considering their emissionreduction targets and options at this time, with SIP revisions due onNovember 15, 1993.E. Better Data and Models Are NeededSeveral steps are required to analyze the emissions consequences ofregional transportation plans or measures designed to control travelbehavior. First, based on the existing development and land usepatterns, a regional transportation modeling system is typically usedto estimate a baseline volume and pattern of travel. Second, theresulting estimate of total travel broken down by vehicle type, timeperiod, speed, or other important category are used in conjunctionwith a vehicle emissions model to predict regionwide emissions ofdifferent pollutants. Next, these same steps are repeated with thetransportation plan or control measure in effect, and the predictedemissions are compared to the baseline estimates. (See Appendix F fora complete description of the transportation and emissions modellingprocesses.) The regional transportation modeling system currently used to estimatetravel volumes and patterns was designed 30 years ago. This systemwas originally intended to forecast the need for new highwayfacilities, and today has far greater demands placed on it with suchCAA and ISTEA policy implications as air quality modeling. Thoughuseful when applied in the traditional role of determining how manylanes are necessary to serve a particular region, these models are notsensitive to many of the inputs and parameters needed for theiradaptation to air quality modeling. Short-term improvements to thecurrent transportation model set have the potential of satisfying manyof the gaps in the air quality model link. Other deficiencies,however, point to a need for more in depth research into newprocedures and algorithms. The ability to translate a transportation plan to influence travelbehavior into changes in inputs for the regional models is a criticalstep in this process. Each individual project comprising atransportation plan or TIP can potentially alter the configuration orcapacity of the regional transportation network. Any changes arereflected in the computerized representation of the network byaltering the capacity or performance characteristics. The results ofa number of such changes implemented together, such as would occur ifall of the projects included in a regional transportation plan wereconstructed, are estimated by operating the system of regionaltransportation models with the reconfigured network substituted forthe original network.Translating many TCMs into corresponding changes in regionwide travelpatterns and vehicle emissions is more challenging. The averagetravel and emissions impacts of capital-intensive TCMs, such as newtransit facilities or HOV lanes, are usually evaluated in much thesame way as individual elements of the regional transportation plan. However, expressing the effects of measures such as mandates foremployers to encourage or require flexible work schedules or mandatesfor employer-based ridesharing promotion programs in a regionalmodeling system is considerably more difficult. Assessing theemissions consequences of these measures is likely to require morecreative, detailed, and localized analysis, which in many cases can beconducted most effectively outside the framework of conventionalregional transportation and vehicle emissions modeling. Taken together, both transportation and emissions models must makevarious technical and behavioral assumptions. Such assumptions oftenfall short of accurately representing an extremely complex reality. 1. Uncertainty in Transportation, Emissions and Concentration ModelsInaccurate estimates of regional vehicle emissions associated withurban travel can result from errors in either the detailed estimatesof traffic volumes and speeds produced by transportation models, orthe emissions rates for the fleet of vehicles operating in an urbanarea. The accuracy of these estimates is tied to the data inputs,mathematical structure, and solution procedures of commonly usedregional transportation and vehicle emissions models.There are three primary sources for inaccuracy in the execution ofregional transportation models: limitations to the inputs on whichthese models rely, areas where the models need to be expanded, andshortcomings in the models themselves. As an example of the former,the forecasted distribution of regional population and employment isoften an erroneous input because such information is dependent onfluctuating political compromises more than on technical expertise. Local officials who want forecasts to reflect positive growth anddevelopment within their jurisdictions sometimes assume successfulimplementation of land-use plans that later prove difficult to adoptor enforce. Aside from their unavoidably controversial nature, thefuture geographic distributions of human activity are likewiseinherently difficult to predict at the level of detail demanded forinput into regional transportation models. In practice, errorssometimes occur if adjustments are not made to improve accuracy. Forecasting can be improved by including additional transportationalternatives in the models. For example, incorporating variables for,and better estimates of, bike and pedestrian mode shares can providemore reliable results than is sometimes done.Nevertheless, many of the errors which occur lie in the nature ofadopting a process for a purpose other than for which it wasoriginally intended. As an illustrative point--travel by time of dayis not necessary for the traditional travel model to estimate regionaldemand, though it is a critical input for air quality modeling. Thehandling of time of day variables lies outside the basic structure ofthe regional transportation model.Input errors also arise from the reliance of many regional modelsystems on incomplete or outdated databases. In particular,information on the volume, geographic pattern, and timing oftripmaking is often estimated from household surveys administered 20or more years earlier. Though an attempt is sometimes made to updatesuch data with limited surveys or public sources such as the U.S.Census, the availability of variables which explain travel behaviorand changing trends may be insufficient. One particularly significant gap between the regional transportationmodels and those used for air quality planning lies in the area ofspeed estimates. Though accurate speeds are a critical input forestimating emissions, the traditional travel model process was notintended as a source for such information. The accuracy of volume andspeed estimates from a regional transportation model may becomeincreasingly unreliable under congested conditions; this serves as anarea of concern for many urban highway networks with prevalentcongestion and high volumes in the peak hour. The limitation ofunreliable speed estimates is also serious for areas with majorarterial streets because congestion-related delays on these facilitiesstem from a complex interaction between directional traffic volumesand traffic signal phasing. The representation of such complexitiesis an application which goes beyond the design of the traditionaltravel model system.Vehicle emissions models can err in basic emission rates forindividual vehicles, as well as in the correction factors used toadjust these measured rates. Basic emission rates are measured for asimulated pattern of "typical" city driving, which does not accuratelyreflect the variety of road facilities, vehicle types and traffic flowconditions encountered in urban travel. Most important, the overallaverage speed (19.6 mph) of the test cycle may not reflect the actualmix of speeds on local roads and highways. It is excessive for localtrips primarily on collector and arterial streets and underrepresentstravel at freeway speeds which now comprises much of urban travel,particularly off-peak.Another source of error is that basic emission rates for specificvehicles, categorized by type, model year, and age, represent testmeasurements from a small sample of vehicles. This is particularlytrue for rate estimates for emissions due to fuel vapor. Yet emissionrates among individual vehicles within any category vary widely evenunder laboratory conditions, so that a small sample may not produce areliable estimate of emissions. It may be possible to reduce thisproblem by using test results from state vehicle emissions inspectionand maintenance programs, once they introduce more realistic, massbased test procedures and standardized reporting requirements takeeffect.The correction factors used to adjust measured emissions rates mayalso be a source of error, particularly the adjustment factorsintended to correct for speeds different from the 19.6 mph average inthe Federal Test Procedure (FTP). MOBILE model speed correctionfactors are developed by interpolating between FTP-measured emissionrates and those measured for other test driving cycles, each of whichgenerates a different average speed. However, actual patterns ofurban driving may differ from test cycles in other critical aspects,even with similar average speeds. Frequency and duration of highacceleration periods, for example, may be different from test cycles. EPA has a major effort underway to better characterize cycle aspects,which will be reflected in the emissions model in 2 years. 2. Improving Transportation, Emissions and Concentration ModelsIn November 1994, nonattainment areas designated serious and above forozone must submit SIP revisions that demonstrate their plans aresufficient to achieve attainment of the NAAQS by the CAA-mandateddates. That demonstration will be done in part through use oftransportation, emission, and concentration models. But it is notcertain that strategies developed with these models will ensureattainment. This goal of emission estimations beyond planning formobility stretches the state of the art in transportation/air qualitymodelling to its limits.Current regional transportation and air quality models are unlikely toperfectly reflect actual emissions impacts of transportation plans andprograms. There is a need for broader application and greaterresponsiveness in the models which increases the practitioners'ability to analyze air quality impacts, as well as other aspects oftransportation projects. To this end, efforts to improve thereliability of current models have been widely initiated. A priority initiative has been launched to improve the currentregional travel forecasting models, and to better handle the landuse/transportation relationship. Jointly funded by FHWA, FTA, andEPA, this initiative is significant; under FHWA's lead, the project islikely to encompass many years. Research has begun, and the finalplan for the effort is currently being prepared. The overall effortincludes an outreach program, improving existing procedures,researching new procedures, and a focus on data collection. Includedwill be research into the "supply side" of different modes, focusingon the access of both activities and different times of day. Revisednetwork procedures, in response to changing forecasting needs, willinclude incremental loadings by time of day, embedded in a simulationprocedure which will feedback network information to an "activitygeneration" step. This feedback process should increase thereliability of speeds and volumes under congested conditions. Theoverall model design must be flexible and sensitive to changes inneeds of decision makers and to changes in air pollution controltechnology. Vehicle emissions models can also be improved, and EPA conducts anongoing program of research and testing that has led to continuingimprovements in its MOBILE emissions model. A source of potentialerror in vehicle emissions models has been the inability of the testdriving cycle to represent the variety and mix of vehicle operatingconditions encountered in typical urban driving. Currently, EPA isworking to correct this potential error through a large scale researcheffort to determine actual in-use driving behavior and the emissionimpacts as compared to the FTP. To ensure that vehicles are beingtested under circumstances which reflect the actual current drivingconditions, EPA found potential concerns with the FTP's treatment ofacceleration, speed, soak time and, cold start driving behavior duringan earlier review.EPA was unable to sufficiently address the aforementioned problemsbefore the CAA deadline for correcting and producing a new FTP. Consequently, EPA is operating under a court mandated schedule, tocomplete the new FTP. Under the court mandated schedule EPA must: produce a first draft of the FTP NPRM by October 1993, publish theNPRM by March 30, 1994, and promulgate the final rule by December 31,1994.F. Beyond Transportation - Land Use, Public Acceptance, and Fiscal Constraints Figure ProminentlyThe Clean Air Act and ISTEA set forth challenging goals which becomeeven more challenging when taken together. ISTEA clearly sets forth apolicy that transportation investments and strategies must meetsocial, environmental, and economic objectives while meeting theNation's mobility goals. The Clean Air Act, as amended, is designedto attain and maintain the NAAQS. The combination of these Acts haschanged the way transportation planning will be done in areas failingto meet the NAAQS. The challenges to air quality and transportation planners in jointlymeeting these objectives are numerous and complex. There areimportant factors which are part of the background in whichtransportation and air quality planners must operate, but which arebeyond control of any single government entity. These factors includethe importance of land use in influencing transportation demand andair quality, the lack of public understanding of benefits of cleanair, and competing urban priorities under constrained fiscalconditions.1. Land UseWe are becoming increasingly aware of the interrelationships of landuse and transportation. Low density development often means that thepreponderance of trips can only be made by the automobile. Thislimits travel for those who cannot drive or afford an automobile. Simliarly, higher density land use better supports public transitservices. "The pattern of urban development dictates whether people can walk or cycle to work or whether they must travel dozens of miles; it also determines whether a new bus or rail line can attract enough riders. Despite this obvious link, city layouts often are too dispersed to foster efficient transportation." [Marcia D. Lowe, Worldwatch Institute, in Surface Transportation Policy Project Bulletin, October 1992.] While transportation facilities influence growth patterns, there aremany variables which combine to influence growth and land use. Landuse is regulated by local governments, usually under authority grantedby state governments. However, policies at all levels of governmentaffect land use decisions and individual preferences to live orconduct business at a specific location. Economic factors such asdemand for housing and office space are particularly important. Taxpolicies at all levels of government have an influence on land use. For example, income tax deductions for mortgage interest have provideda major incentive for purchase of single family homes. Local realestate taxes, especially differences in taxes among localjurisdictions. also have an influence on location decisions. Theextent of land use regulation is often a factor in decisions bydevelopers. Availability of water, sewer, and other infrastructurealso influence development decisions. ISTEA requires metropolitan and state transportation plans to reflectconsideration of land use plans. This will be an important step. Better understanding of the relationships between land use patterns,travel patterns and air quality will be needed to respond to thechallenge of reducing transportation's contributions to air quality. Cities such as Portland, Oregon, are studying what can be done toencourage land use patterns which support more efficienttransportation. Changing land use poses significant politicalchallenges and may not yield results within the CAA timeframes.2. Public Acceptance Transportation control measures seek to provide incentives to use moreefficient, less polluting modes of transportation and/or disincentivesto use of automobiles with single occupants. Local decisionmakers insome areas have difficult choices to make in the near future as totransportation plans and transportation control measures in SIPs ifthey are to achieve significant emission reductions from TCMs. The public needs to understand the overall emissions requirements ofCAA, benefits of reduced emissions and the ability of variousstrategies to achieve the benefits. Public acceptance of measuresthat impose higher costs or constraints on SOV travel will beimportant to the success of the transportation control measure and itseffectiveness in reducing emissions.A recent example in the Washington, D.C., area highlights how thefailure to gain public support can lead to a measure's demise. OnSeptember 1, 1992, the Virginia Department of Transportation (VDOT)started operating new lanes on the Dulles Toll Road in the HOV mode,as agreed to by relevant transportation agencies. The toll road, builtto handle 47,000 vehicles per day, was carrying 76,000 in 1992, withprojected volumes to double by the year 2010 unless mitigationmeasures (HOV operation) were adopted. The operation limited the leftlane to carpools of three or more persons. While the facilityaccommodated about 650 3-person carpools during its first weeks ofoperation, the closure of the lane to general traffic caused greatercongestion on the other 2 lanes. This created a furor among SOVusers, worsened by a lack of support from traffic reporters and aperception that the new lanes were underutilized. Neitherenvironmental organizations nor local politicians rallied to supportthe HOV proposal. Bowing to overwhelming pressure from congressionalrepresentatives and motorists, Virginia's Commonwealth TransportationBoard suspended the HOV restrictions on October 5, 1992. To give HOV lanes and other control measures a greater chance ofsuccess and to avoid commitments to measures where they cannotsucceed, the public must have an opportunity to participate in thetransportation and air quality planning processes. ISTEA expandsopportunities for public participation in state and MPO transportationplanning. 3. Fiscal ConstraintsAt all levels of government, there is a paradox of increasingrequirements for staff time, analysis, and other resources while atthe same time fiscal constraints are increasing. For example, theanalysis required to support determinations that transportation plansand programs conform to air quality plans will be extensive. For mostareas, this will cost about $50,000 for the conformity determinationalone. However, costs can be very significant, perhaps reachinghundreds of thousands of dollars, as in the case of Los Angeles. Further, the conformity analysis will have to be repeated each timerevisions to a plan or program are proposed. Development of emissionsinventories, budgets, and other elements of state implementation plansalso require substantial expenditures by air quality agencies. At thesame time, all levels of government are facing hard decisions aboutbudget shortfalls. Other concerns not related to transportation andair quality are important and fighting for limited resources.III. STATUS OF PROGRAMSA. Full Funding of ISTEA Would Help Meet Mobility and Air Quality Goals1. Funding Levels for Title I Programs (Surface Transportation)Expensive, capital-intensive projects may not be the best use oftransportation funds for air quality, but current funding is stillneeded to improve alternatives to SOV travel and reduce emissionsthrough effective programs like enhanced inspection and maintenance,among others. Funding levels are authorized in ISTEA, and yearlylimits are placed on total expenditures by the Congress through theappropriations process. In 1993, appropriated amounts for Title IPrograms (for Surface Transportation) were considerably less than theISTEA-authorized levels, forcing the states with nonattainment areasto make hard choices regarding how to meet both their mobility and airquality goals despite overall increases in authorized funding levels.ISTEA substantially increased funds for air quality purposes in twoways: by creating a dedicated source of funds in the $6 billion CMAQProgram and by providing the flexibility to use funds fortransportation projects which may improve air quality. ISTEA'sflexibility allows $23.9 billion in Surface Transportation Programfunds to be used for transit and other transportation projects andprograms that can have a positive impact on air quality. Furthermore,funds from other ISTEA programs can be transferred to STP and used foreligible purposes under that program. Fifty percent of NHS funds canbe transferred to STP without Federal approval, and 100 percent can betransferred with DOT approval. Forty percent of Bridge funds and 20percent of Interstate Maintenance funds can also be transferred toSTP. Table 3 Summary of Major ISTEA/Title I ProgramsClick HERE for graphic.ISTEA also increased the quantity of funds available for planningpurposes, needed to support both transportation and environmentalprograms. Metropolitan planning is funded by a legislated set asidefrom NHS, STP, CMAQ, Interstate Maintenance, and Bridges. Thepercentage of planning funds doubled from 0.5 percent to 1.0 percentunder ISTEA and the actual dollar amount more than doubled ($47million in FY 1991 to $117 million in FY 1992) because of the higherauthorization level. Highway Planning and Research (HPR) fundssimilarly increased from 1.5 percent to 2.0 percent. Finally,planning and research are eligible activities under both NHS and STP.The ISTEA-authorized levels, however, have not been realized. In theappropriations for FY 1993, the obligation ceiling--the maximum amountof annual Federal aid funds the states are allowed to spend under allprograms--was set significantly below the authorized amount. As Table4 shows, an additional $2.9 billion could have been included in theobligation ceiling and spent on needed transportation and air qualityprojects.Current funding is needed for transportation programs to improve airquality, but setting the obligation ceiling below authorized levelsfurther constrains the already difficult choice that states must maketo meet both their mobility and air quality needs. Priorities willdiffer from state to state, but by appropriating less than authorizedlevels, Congress makes those choices all the more difficult. And eventhough $967 million was apportioned to the states under the CMAQProgram in 1993, the states will not have the opportunity to make fulluse of the funds for air quality purposes if their obligation ceiling isreached by advancing other needed transportation projects. Table 4 Authorized vs. Appropriated Levels for Title I Programs 1993Click HERE for graphic.2. Funding Levels for Title III Programs (Federal Transit Act)In FY 1992, the total authorized funding level under Title III ofISTEA (which amends the Federal Transit Act) was $3.64 billion,including $2.29 billion for the formula grants program and $1.34billion authorized for discretionary grants. The enacted budget forFY 1992 very nearly matched authorized funding levels for that year.For FY 1993, the funding picture changed markedly. FTA's totalauthorization for FY 1993 increased significantly to $5.23 billion,including $3.2 billion for the formula grants program and $2.03billion for discretionary grants. The FY 1993 enacted budget,however, provided only $1.7 billion for formula grants and $1.72billion for discretionary grants.The greatest shortfall in appropriations was in the formula grantprogram where $758.26 million was appropriated for capital grantsunder the Section 9 urban formula program as compared to a total of$1.02 billion for the previous fiscal year. This level of funding forthe Section 9 capital program in FY 1993 detracted from the ability oftransit agencies to advance needed capital improvement projects. Funding was insufficient to allow transit agencies to upgrade andexpand service at a time when Clean Air Act requirements wouldencourage an expanded role for transit in nonattainment areas.The disparity between authorized and appropriated funding levels isalso evident for transit's metropolitan planning. MPOs rely heavilyon FTA's Section 8 planning funds to conduct long- and short-rangetransportation planning which meets CAA requirements. In FY 1993, $70.67 million was authorized for metropolitan planning but only$38.25 million was appropriated.The magnitude of this shortfall for metropolitan planning seriouslyundercut the ability of MPO's to acquire the technical capabilitiesthat they need in order to satisfy the new CAA requirements. Unquestionably, CAA placed a significantly greater analytical burdenon state DOTs and MPOs in demonstrating that their plans and programsconform to the objectives of the SIP.3. The CMAQ ProgramISTEA created a $6 billion authorization for the CMAQ Program over 6years. Approximately $1.8 billion has been apportioned among thestates based on the severity of ozone pollution and the number ofpeople affected. During FY 1992, $340 million was obligated under theCMAQ Program, more than 50 percent of which was assigned to transitcapital projects and about 40 percent for highway purposes (includingHOV lanes, traffic surveillance and incident management, andsignalization and intersection improvements). (See Figure 7.) Othertypical projects and programs included:- establishment of inspection and maintenance programs,- projects to enhance pedestrian and bicycle transportation,- ridesharing programs, and- park-and-ride lots.Click HERE for graphic.As noted above, the CMAQ Program has clearly been the most utilizedsource of flexible funds under ISTEA to date, based on FY 1992obligations. By contrast, the nationwide total of STP funds whichstates made available for transit use was only $24 million, or about0.5 percent of the total STP funds available in FY 1992. Thus, atleast during the first year of the current authorization, the STPprogram was generally used for traditional highway projects while theCMAQ Program provided the great bulk of Title I funds that were put totransit use.The CMAQ Program is tightly focused on the need to bring nonattainmentareas into attainment, but each state receives a minimum apportionmentof at least 0.5 percent of each year's authorization. Twenty-sixstates, the District of Columbia, and Puerto Rico received the minimumapportionment specified by law (almost $9 million each so far). Thirteen of these have no ozone or carbon monoxide nonattainment areasand may, therefore, spend the funds on any project eligible undereither the CMAQ or STP Program. Only 24 states receive more than theminimum apportionment because of their air quality problems. Due tothe statutory apportionment formula, which gives added weight to themore seriously polluted nonattainment areas, these states received 86percent of all the CMAQ Program funds distributed thus far.The states have been slow to obligate their available funds. In FY1992, approximately $340 million was obligated for programs andprojects, representing a 42-percent obligation rate. The lowobligation rate is due to the fact that the program breaks new ground,and initially nonattainment areas struggled with how to best use thefunds. As states and MPOs become more familiar with the programgenerally--and specifically, DOT guidance on project eligibility--andthe needed coordination is fostered between transportation and airquality agencies, the obligation rate is expected to increase. Furthermore, as TCMs are included in SIPs which are subsequentlyapproved by EPA, the demand for CMAQ funds will increase, also raisingthe obligation rate.B. Limited CAA Funds Exist for Air Quality Operations and ManagementFour sections of CAA allow the EPA Administrator to provide funding tostate and local governments, and other public and private groups andindividuals:- Section 103 - provides grants for research and demonstrations relating to the causes, effects and control of air pollution.- Section 105 - provides grants for general air pollution mitigation. For FY 1993, $94.1 million was allocated for Section 103, 105, and 106 programs.- Section 106 - provides for the development of interstate air quality agencies or commissions.o Section 175 - provides funds for developing a plan revision. Although authorized, no appropriations have been made under Section 175.Two additional EPA programs are designed specifically to reduce mobilesource emissions: The CAA Increments Program and Selected NationalPriorities program. The CAA Increments Program sets aside $9.0million (FY 1993) for program development of I/M programs, Stage IIregulations, planning studies, enhanced monitoring activities and public outreach. The Selected National Priorities Program wasallocated $1.8 million for emission-reduction demonstration projectsbased on market and other initiatives.C. Regulations and Guidance Implementing CAA and ISTEA Have Been Issued1. CAA Regulations and GuidanceThis summarizes the status of EPA and DOT efforts to implement thetransportation-related CAA requirements. Regulations and guidance inseveral areas are covered below, including: transportationconformity, transportation control measures, VMT forecasting andtracking guidance, transportation and air quality planning guidelines,motor vehicle inspection and maintenance, mobile source modeling,clean fuel fleet programs, and other related provisions.1.a. Transportation ConformityCAA requires that the Federal Government shall not support or approveany activity which does not conform to an approved SIP. Nometropolitan planning organization (MPO) shall approve anytransportation plan, program, or project, which does not conform tothe applicable implementation plan. The assurance of conformity is anaffirmative responsibility of DOT and the affected MPO. They also require EPA to publish regulations, with the concurrence ofDOT, which lay out the criteria and procedures for determiningconformity of transportation plans, programs and projects that aredeveloped, funded, or approved under Title 23 of the United StatesCode (USC) or the Federal Transit Act. Interim guidance wasdistributed on June 7, 1991. A notice of proposed rulemaking (NPRM)was published in the Federal Register on January 11, 1993. The finalrule is expected to be promulgated by October 1993.1.b. Transportation Control MeasuresCAA requires EPA, in consultation with DOT, to publish guidance onupdated information on 16 broadly defined TCMs. The Agency hasproduced a group of documents to satisfy the aforementioned CAArequirements, including the Transportation Control Measure InformationDocuments and the Transportation Control Measure: StateImplementation Plan Guidance. The availability of these documents wasannounced on May 29, 1992. These documents are designed to assiststate and local officials in planning and evaluating transportationcontrol measures. Information is provided through discussions ofimplementation issues, variations of measures, degree ofeffectiveness, and institutional processes. More quantitativeinformation is provided on current methods, strategies, and variablesfor making estimates on how transportation control measures affect thenumber of vehicle trips, vehicle miles traveled, and vehicle speed.EPA is currently working on several documents to augment the guidancelisted above, including information on the estimation of emission andtravel activity effects of TCMs expected in 1993. Guidance on thereduction of work related trips, titled the Employee Commute Options(ECO) program, were issued in January 1993. Three workshops were heldin the spring of 1992 to provide additional guidance. In addition,EPA, DOT, and NARC are sponsoring additional TCM analysis andinformation dissemination for state and local governments.1.c. VMT Forecasting and Tracking GuidanceCAA requires EPA to publish guidance, in consultation with DOT, onforecasting VMT. EPA published the Section 187 VMT Forecasting andTracking Guidance on March 19, 1992. This guidance addresses how toforecast and track VMT in moderate and serious CO nonattainment areaswith design values greater than 12.7 parts per million (ppm). Theguidance states that estimates of actual annual VMT in areas subjectto the Section 187 requirements should be obtained from the HighwayPerformance Monitoring System (HPMS), maintained by DOT. The HPMS VMTestimates will be used to track actual VMT.1.d. Transportation and Air Quality Planning GuidelinesCAA mandates that EPA update and publish the 1978 guidelines onTransportation and Air Quality Planning, in consultation with DOT. EPA published the updated 1992 Transportation and Air Quality PlanningGuidelines. This document is designed to provide guidance to stateand local government officials and to assist them in planning fortransportation related emissions reductions that will contribute tothe attainment and maintenance of the NAAQS for ozone, CO, and PM-10. The notice of availability for the Transportation and Air QualityPlanning Guidelines was published in the Federal Register on August18, 1992.1.e. Clean Fuel Fleet Programs CAA requires the establishment of a program to require certaincentrally fueled fleets to include some clean fuel vehicles in theirnew vehicle purchases. As defined in CAA: 'a clean alternative fuel' means any fuel (including methanol, ethanol, or other alcohols (including any mixture thereof containing 85 percent or more by volume of such alcohol with gasoline or other fuels), reformulated gasoline, diesel, natural gas, liquefied petroleum gas, and hydrogen) or power source (including electricity) used in a clean fuel vehicle that complies with the standards and requirements applicable to such vehicle under this title when using such fuel or power source.Clean fuel vehicles will be required to meet stringent emissionsstandards.The Clean Fuel Fleet Programs involve two rulemakings. The firstestablishes guidelines for a Clean Fuel Fleet credit program,regulations for governing transportation control measure exemptionsfor Clean Fuel Fleet Vehicles, and provisions effecting Federal FleetFacilities. The second rulemaking will include regulations governingthe conversion of conventional vehicles to meet the clean fuelstandards for all vehicle/engine classes, heavy duty engine standards,and general provisions for state implementation of the Clean FuelFleet program.EPA issued an NPRM for TCM exemptions to the Clean Fuel Fleet programon October 3, 1991, and a final rule on March 1, 1993. The rulespecifies which clean fuel vehicles are exempt from transportationcontrol measures, such as time-of-day and HOV lane restrictions. Workon the second rulemaking, concerning emission and conversionrequirements, is underway but no forecast of a promulgation date hasbeen released.1.f. Mobile Source Emissions ModelingSection 130 of CAA requires EPA to review and revise the emissionfactors used to estimate the emissions of CO, VOC, and NOx from mobilesources. EPA has produced a series of computer programs whichincorporate emission factors known as the MOBILE series.In response to CAA, EPA announced the release of MOBILE 4.1 on January4, 1991, and an updated version MOBILE 5.0 on December 4, 1992. Thisupdated model superseded all previous MOBILE series models. MOBILE5will be used for all projection year ozone inventories, and forconsistency, 1990 inventories in ozone areas will have to bereestimated with MOBILE5 also. It may also be used for projection-year CO inventories.1.g. Motor Vehicle Inspection and Maintenance.Each state containing a moderate ozone nonattainment area, and undercertain conditions a marginal area, as well as certain COnonattainment areas, are required to submit a SIP revision dueimmediately after enactment of the 1990 CAA amendments that includesprovisions necessary to provide for a basic vehicle inspection andmaintenance program. Additionally, each state containing seriousozone nonattainment areas or high-moderate CO nonattainment areas, orareas of higher level classifications, are required to submit a SIPrevision to provide for an enhanced vehicle inspection and maintenanceprogram for urban areas of 200,000 or more within 2 years of theenactment of the 1990 amendments. States with metropolitan areasgreater than 100,000 population in an Ozone Transport Region must alsosubmit SIP revisions for this purpose.CAA directs EPA to publish guidance for motor vehicle inspection andmaintenance programs within 12 months of enactment. EPA's guidance onvehicle inspection and maintenance is required to include informationon the frequency of inspections, the types of vehicles to beinspected, vehicle maintenance required by owners and operators,audits by the state, test methods and measures to include whethertesting is centralized or decentralized, inspection methods andprocedures, quality of inspection components covered, assurance that avehicle under recall from a manufacturer has complied with thatnotice, and effective implementation and enforcement, includingassurance that any vehicle retesting after a failure shall includeproof of corrective action. The language in CAA concerning the vehicle inspection and maintenanceguidance is of a legally binding nature not often associated withguidance. After consultation with EPA's Office of General Counsel andafter public hearing and comment, EPA concluded that it was requiredto pursue a rulemaking instead of the publication of guidance forenhanced I/M programs.EPA promulgated a rule for both basic and enhanced vehicle inspectionand maintenance on November 5, 1992.1.h. New Bus Emission StandardsCAA contains several provisions relating to buses which include: anew particulate matter standard, a requirement for retrofitting of1993 and earlier model year urban buses, and new requirements for an"in-use" urban bus test. In addition to and associated with the busprograms, a revised NOx standard for all 1998 and later year heavyduty engines is also contained in CAA. EPA has responded to theaforementioned requirements by pursuing two separate rulemakings, aretrofit rule which was promulgated on April 22, 1993 and a rulecontaining 1994 requirements which was published in the FederalRegister on March 24, 1993.1.i. Related Provisions - General PreambleEPA published the General Preamble for Title I of CAA in the FederalRegister on April 16, 1992. This document provides guidance to stateson how to prepare SIPs that comply with CAA provisions relating to theattainment of the NAAQS. It addresses state submittals under Title Idue during the first 6 years after enactment.2. ISTEA Regulations and GuidanceThe following section provides the status of DOT regulations andguidance relating to air quality.2.a. Procedures for Flexible FundingFHWA and FTA released procedures which govern the use of STP andInterstate Substitution-Highways Program funds for transit projects,and the use of FTA Section 9 Program funds for highway projects inMarch 1992. This was followed in July 1992 by the publication ofprocedures for using CMAQ funds for transit programs and projects.2.b. CMAQ GuidanceFHWA and FTA issued interim guidance on the CMAQ program in February1992 and comprehensive guidance in October 1992. The guidance statesthat TCMs contained in the SIPs have the highest priority for CMAQfunding. In addition, the guidance clarifies what is eligible underCMAQ and emphasizes the need for cooperation between Federal, state,and local governments and agencies in deciding which projects to fundunder the CMAQ program.2.c. Metropolitan and Statewide Planning RegulationsFHWA and FTA issued interim guidance on ISTEA's new metropolitanplanning requirements in April 1992. This guidance covers severalissues related to CAA compliance such as the need for a coordinatedapproach on regional emissions analysis. Additionally, the guidancerequires that projects covering the first 3 years of the TIP beprioritized. An NPRM for the metropolitan planning regulation waspublished on March 2, 1993, along with an NPRM for statewide planning. The comment period closed on May 3. A final rule is being developedand is expected to be issued in late summer 1993. 2.d. Management Systems RegulationsISTEA requires DOT to issue regulations on the state of developmentand implementation of systems for managing: (1) pavement of Federal-aid highways, (2) bridges on and off Federal-aid highways, (3) highwaysafety, (4) traffic congestion, (5) public transportation facilitiesand equipment, and (6) intermodal facilities and systems. Three ofthe management systems (traffic congestion, public transportation, andintermodal) relate to air quality considerations. ISTEA requires thatthe results of these management systems be considered in makingproject selection decisions under Title 23 of the United States Codeand the Federal Transit Act. FHWA and FTA published an NPRM in the Federal Register on March 2,1993. It requires states to implement the aforementioned managementsystems by FY 1995. The NPRM would require identification of areaswhere congestion occurs and its causes, evaluation of strategies tomanage it, and recommended congestion reduction strategies. In theNPRM, priority is given to measures which both reduce SOV travel andimprove the efficiency of the existing system. Issuance of a finalrule is expected by late summer 1993.The public transportation management system proposes a system of datacollection on the age, condition, useful life, and replacement valueof transit facilities and equipment as the basis for choosing the mostcost effective strategies for providing and maintaining transitassets. The proposal envisions an ongoing process of assessing theconditions of the assets of a transit system in order to identify theareas of greatest need.The current proposal of the intermodal management system requires theidentification of intermodal facilities and the use of efficiencymeasures to gauge the performance of facilities and the system as awhole. Data collection at both the project and system level would benecessary to evaluate what measures or actions will promote maximumconnectivity and more efficient linkages across the air, water, andvarious land-based transportation systems.2.e. Congestion Pricing Pilot ProgramIn May 1992, FHWA published a Federal Register Notice announcing acongestion pricing pilot program, administered by FHWA, and designedfor the establishment, maintenance, and monitoring of congestionpricing projects. FHWA published a second Federal Register Notice onNovember 24, 1992, which formally solicited proposals and outlinedevaluation and rating criteria. Competing proposals received by theclose of the proposal period on January 25, 1993, are being evaluatedand rated by an interagency review committee. A second solicitationcould take place, should the initial period result in fewer than thefive cooperative agreements permitted under ISTEA. Table 5 A Summary of Current Guidance/Regulations and Other Documents Published in Fulfillment of ISTEA and CAAClick HERE for graphic.D. SIP Development, Revisions, and EPA Approvals Are ProceedingThis section describes the status of transportation-related SIPsubmittals under CAA. A SIP is a legally enforceable documentsubmitted by the Governor or designee consisting of rules andregulations demonstrating attainment of the NAAQS by the dates setforth in the Act. States are required to submit SIP revisions atspecified points between 1991 and 1994 to meet specific clean airrequirements. EPA expects states to have submitted fully-adopted,technically and administratively complete SIPs and SIP elements by therequired due dates. In a limited number of circumstances, EPA mayaccept "committal SIPs" in lieu of a fully adopted SIP which consistsof a commitment by the state to adopt specific enforceable measureswithin 1 year of the promulgation of EPA's conditional approval of thecommitment.If a state fails to make a SIP submittal by the due date, EPA mustmake a finding of failure to submit a SIP, or an element of a SIP. Ifa finding is made, it will start the 18-month clock for purposes ofimposing 1 of 2 two sanctions provided for in section 179(b) of CAA. This action also activates the 24-month period for FederalImplementation Plan (FIP) promulgation. 1. SIP Revisions for "Reasonably Available Control Technology" (RACT)States were required to submit SIP revisions in May 1991 thatdemonstrate their plans to implement emission control technology onexisting stationary sources that are acceptable to EPA. Theserevisions are noted in this report because of the potential for theimposition of highway sanctions (see below). EPA published itsfinding that 12 areas in 5 states had failed to adequately comply withthe RACT SIP revisions in the Federal Register on October 22, 1991. EPA has a nondiscretionary duty to apply sanctions to any of the 12areas which had not submitted complete and acceptable SIPs beforeApril 22, 1993. State efforts are underway to correct deficiencies inSIP submittals even while administrative procedures are put in placeto impose sanctions.2. PM-10 SIP RevisionsThe first of the mobile source SIP revisions was due on November 15,1991, in which states were required to demonstrate how they will reachattainment for PM-10 by December 31, 1994. Sixty-seven areas wererequired to submit SIP revisions. Forty SIPs were submitted on time;27 were not. During 1992, 8 additional SIPs were submitted. Of theremaining 19 areas, 3 were incomplete and 16 were missing. Sanctionsare required to be imposed on the 16 areas after June 15, 1993. Sanctions will be due in one area submitting an incomplete SIP inSeptember 1993, and the last two in November 1993.3. Ozone and CO SIP Submittals Required on November 15, 1992CAA also required certain SIP submittals for ozone and COnonattainment areas by November 15, 1992. Ozone and carbon monoxideSIPs that have met the November 15, 1992, submittal deadline haveundergone a review to determine the completeness of both the SIPelements and the entire SIP. Letters of failure to submit a SIPelement or an entire SIP were sent from the EPA Regions to 33 states,the District of Columbia, and Puerto Rico on January 15, 1993.In the aforementioned letters, EPA summarized the findings. Ingeneral terms, if a state failed to submit any plan elements, theletter identified the nonattainment areas for which the state did notmake a submittal, identified the specific requirements that were notmet, and made a finding of state failure to submit a required plan orplan element. The letters also explained the statutory consequencesof failure to make a submittal, and the statutory consequences of EPAdisapproval of any submittal. These letters start the 18-monthsanctions clock and the 2-year FIP clock. The number of statesreceiving a letter for failure to submit a SIP are shown in Table 6. They have until July 15, 1994, before sanctions are due to be imposed.Table 6Number of States Failingto Meet 11/15/92 SIP SubmittalsClick HERE f or graphic.4. Future SIP RevisionsBy November 15, 1993, states with moderate ozone nonattainment areasmust submit SIP revisions that demonstrate emission reductions of atleast 15 percent in the first 6 years for volatile organic compounds(VOC) and attainment demonstration SIPs. By November 15, 1994,Serious, Severe, and Extreme ozone areas must submit SIP revisionsthat demonstrate VOC reductions that average 3 percent per year eachconsecutive 3-year period after the initial 6-year period andattainment demonstration SIPs.5. SanctionsUnder Section 179(a) of CAA, EPA must impose sanctions on any statewhich fails to submit a SIP or a portion of a SIP. Under Section179(a), EPA must impose sanctions 18 months after it makes a findingof a missing, incomplete, or inadequate SIP for the purpose ofensuring that the requirements of the Act are met. In unusualcircumstances EPA may be able to impose sanctions earlier than at theend of the 18-month period under Section 110(m). EPA published aproposed rule in the Federal Register on September 28, 1992,explaining the criteria for sanction determinations. A final rule isexpected in late 1993.One of two sanctions is applied to states not meeting the relevant CAArequirements: sanctions on Federal highway funds or sanctions on newstationary source emissions ("2:1 offsets"). If highway sanctions areapplied, no Federal highway funds, with some exceptions, may beobligated for projects in the area failing to meet SIP submissionrequirements. Nine categories, describing projects largely related toTCMs and safety, are exempt from sanctions. After 24 months followingthe SIP submittal deadline, EPA can impose highway sanctionsstatewide. If 2:1 offset sanctions are imposed, EPA requires a 2-tonemission reduction for each ton of emissions coming from new ormodified stationary sources that increase emissions in the area. Ifthe deficiency has not been corrected within 24 months, EPA mustimpose both sanctions.As of March 1993, EPA had notified 37 states that they have failed tomeet deadlines for submittal of various CAA requirements and are underthreat of sanctions. Sanctions were due in five states as of April22, 1993.For EPA to impose sanctions, EPA must select whether the highwaysanction or the general offset ratio sanction will be applied first. EPA has determined that this selection is a rule under theAdministrative Procedures Act, which means EPA must propose and allowthe public to comment on its selection. Sanctions will begin to applyin the affected areas when EPA completes this selection rulemaking.E. Transportation Plans, TIPs, and Conformity Determinations Are Also ProceedingEnactment of CAA and ISTEA significantly changed the wayTransportation Plans and TIPs are developed in nonattainment areas. Where previously they were developed primarily to address a region'smobility needs, now these Plans and TIPs must also contribute toimprovements in air quality in nonattainment areas.This section describes the status of Plan and TIP development innonattainment areas since enactment of CAA and ISTEA. This sectionalso summarizes conformity determinations made on TIPs by MPOs andDOT.1. Plan and TIP DevelopmentBased on a survey of MPOs done under the auspices of NARC in September1992, most nonattainment areas are in the process of developingtransportation strategies to improve air quality. These strategiescan include various projects and programs to reduce emissions,including transportation control measures. However, development andimplementation of new strategies to improve air quality are still intheir early stages, particularly in ozone areas. This isunderstandable because MPOs in nonattainment areas are not expected toupdate their Transportation Plans until later this year (October1993), and further SIP revisions are not required until November 1993and 1994. As such, not many MPOs have as yet incorporated these TCMsinto their Plans, TIPs, or transportation elements of SIPs.The overwhelming majority of MPOs in ozone nonattainment areas arecurrently developing new strategies (and TCMs where necessary) toaddress their air quality needs. Over 90 percent of the sampled MPOsin areas designated as moderate and above are developingtransportation measures to improve their air quality. Even those MPOsin areas with less critical air quality problems are developingtransportation/air quality plans. In areas designated as marginal,approximately 76 percent of the MPOs report that TCM development isunderway, even though marginal areas are expected to reach attainmentlargely through fleet turnover.Once transportation projects to improve air quality have beendeveloped and determined to be appropriate from an effectiveness andfinancial standpoint, they are included in the SIP (in areas whereTCMs are necessary) and specifically identified. CAA requires theseTCMs to receive priority consideration and expeditious implementation. While MPOs are required to only include FHWA/FTA-funded or -approvedprojects in their Plans and TIPs, the status of all SIP transportationcontrol measures is covered in the TIP submission because of the needto demonstrate expeditious implementation of TCMs in making conformitydeterminations on Plans and TIPs.Despite the large proportion of nonattainment area MPOs seeking waysto effectively reduce emissions, so far only a small proportion reportthat they have incorporated any transportation measures developed as apart of this process into the Plan (25 percent) or TIP (37 percent). Some of the reasons for this relatively low percentage is that eitherSIPs have not been completed or EPA has not yet approved them; or SIPsmay address air quality needs through strategies solely targetingstationary or area sources; or mobile source reductions may beachieved through technological means rather than transportationprograms, and SIPs would not necessarily include specific TCMs thatwould be included in the Plans and TIPs. On the other hand, ifemission reductions from transportation projects and programs are apart of their strategies, these efforts will most likely be includedin Plans and TIPs.2. Conformity DeterminationsThe conformity provisions of CAA will be the most challenging fortransportation planners. Conformity provisions were first added tothe Clean Air Act by section 176(c) of the Act as amended in 1977. This section makes it the affirmative responsibility of the Federalagency supporting an action to ensure that its activities conform toan approved or promulgated air quality implementation plan. It alsoprohibits the MPO from approving any transportation plan, program, orproject which does not conform to such a plan.To ensure continuing conformity between transportation plans andprograms and SIPs, CAA requires that conformity determinations be madeno less frequently than every 3 years. The actual frequency rate willbe established by the EPA conformity regulation. A conforming plan orprogram must be consistent with the area's emissions budget, notcause, create, or worsen violations, not obstruct attainment, anddemonstrate timely TCM implementation.At the project level, the following three conditions need to bedemonstrated in order to make a conformity determination: - The project must come from a conforming Plan and TIP; o the design concept and scope of the project should not have changed significantly since the Plan and TIP were found to conform;- the design concept and scope of the project must be sufficiently developed to determine emissions at the time of the conformity determination for the TIP; and- in CO and PM-10 nonattainment areas, the project must not create or worsen hot spot violations.CAA allows a case-by-case conformity determination for projects notcoming from a Plan and TIP.Most state agencies and MPOs in nonattainment areas have now beenthrough two rounds of conformity determinations under CAA. Most ofthese agencies spent a considerable amount of staff resources andfunds to complete the required analysis; and some are currently undera threat of litigation by environmental groups that see the conformityprocess as a means of forcing a change in the transportationdecisionmaking process. In most areas, the conformity requirement has made a major differencein the development and acceptance of Transportation Plans and TIPs. This has occurred in various ways, and can be best illustrated by thefollowing examples.- FHWA and FTA withheld acceptance of certain TIPs from the Great Lakes area for 4 months until the public had the opportunity to comment on them and the MPOs responded. Future improvements in MPO modeling and technical process was also a condition for TIP acceptance in these nonattainment areas.- In several midwest areas, only the "neutral" projects within the TIPs were found to be in conformity. Neutral projects are defined as those with minimal air quality impacts and can proceed without a conformity analysis. MPOs in these areas were required to improve their models used to make conformity determinations. In other areas in Ohio and Indiana, for example, MPOs themselves submitted TIPs comprised only of neutral projects while they adjusted to the new analysis requirements.- In the southeast and northwest parts of the country, highway projects were delayed until the TIP containing the conformity analysis was completed. In some cases, this meant that projects were withheld from the Statewide TIP until a TIP conformity analysis was completed.- One area in the southwest reported that innovative projects contributing to improved air quality have been accelerated as a result of the conformity requirements.Throughout the United States, MPOs report that they have had to dropor delay projects previously scheduled for implementation to meet theconformity requirements. The impact of this is that most plan and TIPamendments now consist of only neutral projects due to the constraintsof this complex process.Due to the working relationship that exists between DOT, the statesand MPOs, no nonconformity determinations have been made to date. Intheir analytical processes, the MPOs themselves alleviate mostpotential nonconformity situations prior to formal submission toFederal agencies. In addition, informal Federal review of Plan andTIP development typically avoids the inclusion of projects failing tomeet the conformity test.IV. CONCLUSIONSCAA together with ISTEA call for significant changes in the way we goabout meeting transportation and air quality goals. CAA seeks toreduce vehicle emissions through a combination of cleaner vehicles,cleaner fuels and transportation programs and projects to help achievenational air quality goals. Transportation control measures may playa role in many state air quality implementation plans. Therequirements to determine conformity of transportation plans, programsand projects to state air quality plans dictate consideration of airquality concerns in transportation planning and project development. The ISTEA complements the Clean Air Act by giving state and localtransportation officials the flexibility to use Federal transportationfunds in ways that will help develop a balanced, environmentallysound, intermodal transportation system. ISTEA increases the emphasison multimodal considerations, land use decisions and air qualityproblems in the transportation planning process and on publicparticipation in transportation planning. New ISTEA programs, such asthe Congestion Mitigation and Air Quality Improvement Program wereestablished to help fund transportation control measures and otherprojects intended to help meet standards in air quality nonattainmentareas. Other programs such as the congestion pricing pilot programmay also offer air quality benefits, although the details ofimplementing these projects remain to be worked out.These two statutes together call for fundamental changes in thetransportation and air quality planning processes. It is too early tojudge the extent to which the intended process changes have occurred. Transportation agencies are just beginning to take advantage of theflexibility and new programs offered by ISTEA. New players in thetransportation planning process are just beginning to become involvedin many areas. Development of state air quality implementation planswill continue for ozone and other pollutants at least until late 1994. Because we are still assessing how transportation and air qualityagencies are responding to CAA and ISTEA, this report does not offerconclusions on how well new programs and requirements are working. Legislative recommendations are not offered at this time. Buttremendous challenges remain to be met in responding to these newrequirements, including the following: - Mobile source emissions have decreased considerably since the early 1970s due to the improvements in automobile technology, but future long term reductions are in doubt. Transportation trends show increasing VMT, while shared rides and transit are decreasing. VMT increases could counteract important progress made over the last 10 years in producing cleaner vehicles and retard attainment efforts.- Traditional methods of altering transportation behavior such as construction of transit and high occupancy vehicle lanes have not been shown to substantially reduce pollution. Preliminary indications from several areas in the country show that traditional transportation control measures alone will only yield a 1 to 2- percent reduction in air pollutant emissions. Significant potential for further progress can also be made through technological improvements by reducing cold start, tailpipe, and evaporative emissions. Substantial changes in the level of TCM effectiveness will need to offer a comprehensive program of TCMs, including both the traditional TCMs and economic/marketing based TCMs such as congestion/road pricing, increases in parking prices, and emissions or VMT charges. Such a comprehensive program would need to combine transportation choices and measures to discourage trips in single occupant vehicles.o The complex requirements of CAA and ISTEA have increased the burdens on staffs of local transportation and air quality agencies, as well as federal agencies, and increased the complexity of issues which need to be considered by decisionmakers.- Transportation and air quality modeling tools need to be upgraded to be useful in meeting these increased requirements.- Our knowledge of the interrelationships between land use, economics, demography and transportation is still developing, but the reciprocal interaction of two factors seems to be a significant driving force. Land use densities and travel costs have decreased simultaneously across the country. Even as lower densities increased reliance on the auto, real decreases in the cost of driving and travel subsidies caused further density decreases. The resulting growth in travel produced increases in emissions (prior to the introduction of tailpipe standards). Because both economics and development patterns contributed to our current pollution levels, changes in both may be necessary for improvements in air quality. These will require a sustained effort over many years and will take meaningful land management policies at the local level.Progress is being made in addressing these challenges, but substantialcontinued efforts are needed.- DOT and EPA are working with groups like the National Association of Regional Councils and the Surface Transportation Policy Project to educate state and local agencies on the provisions of the acts through the NARC Clean Air Project and the STPP Livable Communities conferences. These organizations are also involved in helping to develop new coordination and public involvement processes in transportation and air quality planning. Continuation of these efforts will be important. - DOT and EPA are working to develop and distribute guidance to assist areas in meeting the new requirements. Guidance has been issued, but some important regulations have not yet been finalized.While future success depends on our response to the challenges facingus, significant progress has been made. EPA's Air Quality TrendsReport for 1991 showed that 41 of the 97 nonattainment areas for ozoneand 13 of the 42 areas for CO have met the standards for the last 3years. Smog decreased by 8 percent, and CO levels are down 30percent, although not all areas have demonstrated such improvementsand some new nonattainment areas are appearing, especially for PM-10. Major reductions in vehicle emissions have been made, and furtherreductions continue as fleet turnover occurs and more stringentemissions standards come into effect. Implementation of basic andenhanced inspection and maintenance programs in many areas willsubstantially assist this effort and reduce the disproportionateimpacts of gross emitters. Increasing use of reformulated fuels,oxygenated fuels, fuel with lower vapor pressure limits andimprovements in alternative fuels will further reduce vehicleemissions. All of these will make important contributions toattainment of national ambient air quality standards. APPENDIX A CLEAN AIR ACTSECTION 108(f)(3)(3) The Secretary of Transportation and the [EPA] Administrator shallsubmit to Congress by January 1, 1993, and every 3 years thereafter areport that - (A) reviews and analyzes existing State and local air quality- related transportation programs, including specifically any analyses of whether adequate funding is available to complete transportation projects identified in State implementation plans in the time required by applicable State implementation plans and any Federal efforts to promote those programs; (B) evaluates the extent to which the Department of Transportation's existing air quality-related transportation programs and such Department's proposed budget will achieve the goals of and compliance with this Act; and (C) recommends what, if any, changes to such existing programs and proposed budget as well as any statutory authority relating to air quality-related transportation programs that would improve the achievement of the goals of and compliance with the Clean Air Act.(4) In each report to Congress after the first report required underparagraph (3), the Secretary of Transportation shall include adescription of the actions taken to implement the changes recommendedin the preceding report. APPENDIX B SPECIFIC TRANSPORTATION-RELATED PROVISIONS OF THE CLEAN AIR ACT AS AMENDED IN 1990 FOR OZONE NONATTAINMENT AREA CLASSIFICATIONS Marginal - These areas exceed the ozone standard of .12 parts per million (ppm) by 15 percent or less (.121 ppm up to .138 ppm), and are required to attain the standard within 3 years of enactment (11/15/93). - Emission inventories are due within 2 years of enactment. Revised emission inventories are required at the end of each 3-year period until attainment. - These areas must correct existing or previously required inspection/maintenance (I/M) programs. - These areas will be reclassified as moderate nonattainment areas if they fail to attain the standard by the deadline (plus up to two 1-year available extensions).Moderate - These areas exceed the standard by 15 percent to 33 percent (.138 ppm to .160 ppm), and are required to attain the standard in 6 years (11/15/96). Moderate areas must meet marginal area requirements. - In addition to meeting marginal area requirements, moderate areas have to submit SIP revisions within 3 years of enactment demonstrating volatile organic compound (VOC) reductions, within 6 years of enactment of at least a 15 percent from 1990 baseline emissions, while accounting for any growth in emissions after enactment. (Additional requirements for major Nox sources apply in certain areas). - Contingency measures to be implemented if the area fails to make reasonable further progress or attain the NAAQS by the attainment date, these measures are to be included in the SIP and are to take effect without further action by the state or EPA. - These areas must adopt basic I/M programs. - These areas will be reclassified as serious nonattainment areas if they fail to attain the standard by the deadline (plus up to two 1-year available extensions).Serious - These areas exceed the standard by 33 percent to 50 percent (.160 ppm to .180 ppm), and are required to attain the standards in 9 years (11/15/99). Serious areas must meet moderate area requirements. - In addition to meeting moderate area requirements, these areas have to submit SIP revisions within 4 years of enactment that demonstrate VOC reductions that average 3 percent per year each consecutive 3-year period beginning 6 years after enactment. - These areas must submit SIP revisions within 42 months of enactment establishing clean-fuel vehicle programs, mandating that certain percentages of new fleet vehicles be clean-fuel vehicles and use clean-fuels within the nonattainment area, including measures to make the use of clean alternative fuels economical to clean-fuel vehicle owners. - Beginning 6 years after enactment and each 3-year period thereafter, the state has to submit a demonstration as to whether vehicle emissions, congestion levels, vehicle miles traveled (VMT), and other relevant parameters are consistent with those used in the SIP; if not the state has 18 months to submit SIP revisions that include transportation control measures (TCMs) to reduce emissions to levels consistent with SIP levels. - In addition to the contingency provisions required under Section 172(c)(9), the SIP shall provide for implementation of specific measures to be undertaken if the area fails to meet any applicable milestone. - These areas must adopt enhanced I/M programs if the 1980 urban population exceeds 200,000. - These areas will be reclassified as severe nonattainment areas if they fail to attain the standard by the deadline (plus up to two 1- year available extensions).Severe - These areas exceed the standard by 50 percent to 133 percent (.180 ppm - .280 ppm). Areas with design values from .180 - .189 ppm are required to attain the standards in 15 years (11/15/05). Areas with design values from .189 - .280 ppm are required to attain the standards in 17 years (11/15/2007). Severe areas must meet serious area requirements. - In addition to meeting serious area requirements, these areas must submit SIP revisions within 2 years of enactment, which identify and adopt TCMs to offset growth in emissions from growth in trips or VMT. - Within 2 years of enactment, SIP revisions are due that require employers of 100 or more to increase the average passenger occupancy per vehicle for work trips by not less than 25 percent above the average for all work trips in the area. The average vehicle occupancy for the nonattainment area needs to be established at the time of the SIP submittal. The affected employers have to submit compliance plans within 2 years of the SIP revision (within 4 years of enactment) demonstrating compliance not later than 4 years after the revision (within 6 years of enactment). - Severe areas which fail to attain the standard by the deadline are subject to mandatory fees on stationary emission sources and the more stringent new source review requirements applicable to extreme areas.Extreme - The area exceeds the standard by more than 133 percent (.280 ppm and above), and has 20 years to attain (11/15/2010). - Extreme areas must meet severe area requirements. - In addition to meeting severe area requirements, each SIP revision may contain measures to reduce the use of high polluting vehicles or heavy-duty vehicles during heavy traffic hours. - Extreme areas which fail to attain the standard by the deadline must submit a SIP revision within nine months to implement a program of economic incentives and transportation controls.APPENDIX CTRANSPORTATION-RELATED PROVISIONS OF THE CLEAN AIR ACT AS AMENDED IN 1990 FOR CARBON MONOXIDE (CO) NONATTAINMENT AREA CLASSIFICATIONSModerate - These areas exceed the 8-hour CO standard of 9 parts per million (ppm) by not more than 82 percent (9.1 ppm to 16.4 ppm), and are required to attain the standard by December 31, 1995. - Emissions inventories are due within 2 years of enactment with revised inventories no later than September 30, 1995, and no later than the end of each 3-year period thereafter until attainment. - States with CO nonattainment areas which have CO design values of 9.5 ppm and above based on 1988 and 1989 data, or for any 2-year period after 1989, must submit SIP revisions requiring any gasoline sold in the metropolitan statistical area (MSA) or consolidated metropolitan statistical area (CMSA) to contain not less than 2.7 percent oxygen by weight. This requirement must be in effect for not less than 4 months per year. Those areas with design values of 9.5 ppm or more on the date of enactment of CAA must provide for the requirement to take effect no later than November 1, 1992. Areas that reach the design value after enactment must provide for the requirements to take effect no later than November 1, of the third year after the 2-year period for which the design value is determined. - For those areas with design values above 12.7 ppm, State Implementation Plan (SIP) revisions (due no later than 2 years of enactment) have to contain vehicle miles traveled (VMT) forecasts for each year until the attainment date, based on the Environmental Protection Agency's guidance; SIPs have to provide for annual updates of forecasts, and annual reports regarding the forecast accuracy. SIPs must include contingency provisions to be undertaken if actual or projected VMT exceed the prior forecast. - These areas are required to correct existing or previously required inspection and maintenance (I/M) programs, with those areas with design values above 12.7 and a 1980 urban population greater than 200,000 being required to adopt enhanced I/M programs. - These areas will be reclassified as serious nonattainment areas if they fail to attain the standard by the deadline (plus two 1- year available extensions).Serious - These areas exceed the 8-hour CO standard by 83 percent or more (16.5 ppm and higher), and are required to attain by December 31, 2000. Winnebago and Steubenville-Weirton may apply for waivers from mobile source controls, based on a determination, yet to be made, that mobile sources do not contribute significantly to CO levels. - Serious areas have to meet the requirements for moderate areas with design values of 12.7 ppm or greater. - In addition to meeting moderate area requirements, states with serious areas have to submit SIP revisions within 2 years of enactment that include transportation control measures to reduce CO emissions and offset emission increases from growth in VMT, employer trip reduction programs, and require the seasonal use of oxygenated fuel for the MSA or CMSA, whichever is larger. The oxygen content must be sufficient, in combination with other measures, to provide for attainment of the CO standard by the applicable attainment date. The oxygenated fuels requirement is to be in effect no later than October 1, 1993. - Attainment demonstrations have to include annual emission reduction milestones; if the areas fail to meet the milestones, a SIP revision to implement economic incentives and a transportation control program is required.While the relationship of the aforementioned SIP elements totransportation is not always well defined, several programs requiringSIP revisions clearly have an impact upon transportation. Forexample, the conformity provisions of CAA, which are part of a generalmovement towards considering social, economic, and environmental goalsin planning the transportation system, require that transportationplans and programs ensure and support the SIP's goal of attaining theNAAQS. A more complete description of the conformity requirements andthe other transportation-related programs of CAA are contained inSection II of this report.APPENDIX DTRANSPORTATION-RELATED PROVISIONS OF THE CLEAN AIR ACT AS AMENDED IN 1990 FOR PM-10 NONATTAINMENT AREA CLASSIFICATIONAreas designated nonattainment for PM-10 and classified moderate, onNovember 15, 1990, are required by Section 189 of the amended act tosubmit a SIP no later than November 15, 1991. Among otherrequirements, this SIP must include the following two elements: 1) Either a demonstration that the plan will provide for attainment on or before December 31, 1994, or a demonstration that attainment by that date is impractical. 2) Provisions to assure that reasonably available control measures (RACM) for the control of PM-10 are implemented by December 10, 1993.Areas designated nonattainment for PM-10 after November 1990, mustsubmit a SIP within 18 months after being designated nonattainment. States with a moderate nonattainment area are required to submit aplan that includes, among other provisions, a demonstration ofattainment, quantitative milestones and provisions to guarantee thatRACM are implemented. Specific requirements are set forth in subparts1 and 4 of Title I of CAA.Serious AreasThe Administrator of the EPA may classify as a Serious PM-10nonattainment area any moderate PM-10 nonattainment area that theAdministrator determines cannot practicably attain the NAAQS for PM-10by the attainment date or if the Administrator finds that the area hasfailed to attain the standard. Once reclassified as a Serious PM-10nonattainment area, the state must reach attainment of the NAAQS forPM-10 as expeditiously as practicable but no later than the end of the10th calendar year beginning after the area's redesignation asnonattainment. However, areas designated nonattainment for PM-10under Section 107(d)(4) of the Clean Air Act must reach attainment ofthe NAAQS for PM-10 by December 2001.If a Serious PM-10 nonattainment areas fails to attain the NAAQS forPM-10 by the prescribed attainment date, the state shall, afterproviding for both notice and an opportunity for public comment,submit within twelve months after the attainment date, a SIP revisionwhich provides for attainment of the PM-10 NAAQS. From the date ofthe SIP submission until attainment, the SIP shall provide for anannual reduction in PM-10 or PM-10 precursor emissions of not lessthan 5 percent of the total amount of such emissions as reported inthe most recent inventory prepared for the area.APPENDIX ETRANSPORTATION CONTROL MEASURESFROM SECTION 108(f)(1) OF CAA i programs for improved public transit; ii restrictions of certain roads or lanes to, or construction of such roads or lanes for use by, passenger buses or high occupancy vehicles; iii employer-based transportation management plans, including incentives; iv trip reduction ordinances; v traffic flow improvement programs that achieve emission reductions; vi fringe and transportation corridor parking facilities serving multiple occupancy vehicle programs or transit service; vii programs to limit or restrict vehicle use in downtown areas or other areas of emission concentration particularly during periods of peak use; viii programs for the provision of all forms of high-occupancy, shared-ride services; ix programs to limit portions of road surfaces or certain sections of the metropolitan area to the use of non- motorized vehicles or pedestrian use, both as to time and place; x programs for secure bicycle storage facilities and other facilities, including bicycle lanes, for the convenience and protection of bicyclists, in both public and private areas; xi programs to control extended idling of vehicles; xii programs to reduce motor vehicle emissions consistent with Title II, which are caused by extreme cold start conditions; xiii employer sponsored programs to permit flexible work schedules; xiv programs and ordinances to facilitate non-automobile travel, provision and utilization of mass transit, and to generally reduce the need for single-occupant vehicle travel, as part of transportation planning and development efforts of a locality, including programs and ordinances applicable to new shopping centers, special events, and other centers of vehicle activity; xv programs for new construction and major reconstruction of paths, tracks, or areas solely for use by pedestrian or other non-motorized means of transportation when econom- ically feasible and in the public interest; and xvi program to encourage the voluntary removal from use and the marketplace of pre-1980 model year light duty vehicles and pre-1980 light duty trucks. APPENDIX F TRANSPORTATION AND EMISSIONS MODELLINGRegional transportation models were originally developed for use indesigning major capital investments in urban highway facilities toaccommodate anticipated growth in automobile travel. The modelingprocess employs observed regularities in the patterns of household andbusiness activity to make reliable inferences about the volume,location, means, and timing of travel within an urban area, and tosimulate the performance of its transportation system in accommodatingdifferent volumes and patterns of travel.Conducting an analysis of regional travel behavior and transportationsystem performance requires information describing the number andgeographic distributions of households, businesses, and other activitylocations, as well as the demographic and economic characteristics ofhouseholds and individuals, and a detailed description of the spatialconfiguration and performance characteristics of the regionaltransportation network. A complete set of these inputs is requiredfor each period to be analyzed; thus forecasts for each of these areasmust be prepared for each future year under consideration. Analyzingregional travel behavior and transportation system performance alsorequires an integrated set of models and procedures for translatingthe spatial distributions and activity patterns of households andbusinesses into regional travel demands, and for analyzing theinteraction of these demands with the capacity of the regionaltransportation system to accommodate them. Regional travel demand analysis typically proceeds through a sequenceof four modeling steps. In the first of these (termed tripgeneration), the number of trips originating in and destined for eachgeographic zone comprising the region is calculated. Separatecalculations are generally performed for different travel purposes,such as commuting to work, shopping, or recreational travel. The second step links the numbers of trip origins and destinationspredicted for each zone into a specific geographic pattern of travelvolumes or origin-to-destination flows. Such "trip distribution"models typically represent the flow of trips between zones as afunction of total zone trips and some measure of the "difficulty" intraveling between them, usually reflecting a combination of the timeand cost entailed in doing so. In the third modeling step, the interzonal travel flows for each trippurpose are split among travel modes (hence the term "mode split"),using information on the personal characteristics of travelers, aswell as on the comparative costs and performance (speed, frequency,etc.) of the available modes, and is used to produce a total dailytravel matrix by mode. Using external information, this can then beseparated into tables for each time period of interest, most commonlyseparate morning and evening peak travel periods and a single off-peakperiod. In the final modeling step, the trip flows between zone pairs made byeach travel mode during one of these time periods are assigned (hence"traffic assignment") to routes or paths through a regional network oftransportation facilities. The regional automobile network iscomprised of interconnected road and highway segments, while thetransit network consists of individual routes and services,interconnected at passenger transfer points. Assignment proceduresgenerally assume that travelers choose routes to minimize travel time. The traffic assignment process is usually conducted in stages, in anattempt to simulate the diversion of travelers to alternate routes inresponse to congestion on preferred routes. One major complication in the four-step modeling process arises fromthe fact that earlier modeling stages--trip distribution and modesplit--require as inputs the travel times between zone pairs that arethe final outputs of the fourth modeling step, traffic assignment. Acommon response to this interdependence is to estimate provisionalinterzonal travel times for use in those earlier stages, and then torepeat those steps if the more definitive travel times calculated fromthe traffic assignment process differ significantly from provisionalestimates. How many times to repeat this process is currently amatter of debate.An important product of the regional transportation modeling processfor developing vehicle emission estimates is an inventory of totaltravel by vehicle type for each time period included in the analysis. Most traffic assignment models produce estimates of the number ofvehicle-miles traveled (VMT) on facilities represented in the regionalnetwork (such as major arterial streets, highways, and limited-accessexpressways), together with estimates of the resulting average speedof travel on each type of facility. If information regarding thetypical mixes of automobiles and trucks utilizing different types offacilities at different time periods within the day is available, orif parallel regional modeling processes are conducted for automobileand truck travel, separate estimates of VMT by type of vehicle andtime period can also be developed for each facility type. Thisinformation can be used in conjunction with a vehicle emissions modelto estimate total emissions generated by the calculated pattern ofregional travel. Vehicle emission models calculate the rates at which differentpollutants are emitted per mile of travel by various types ofvehicles. These emissions include exhaust gases generated byoperation of their internal combustion engines, and evaporative lossesfrom their fuel systems occurring during vehicle operation, refueling,and storage. Two vehicle emission models are currently in widespreaduse, the EPA's MOBILE model and the EMFAC model developed by theCalifornia Air Resources Board (CARB). Vehicle emissions models consist of an extensive database of emissionsof each pollutant per vehicle-mile of travel measured under controlledoperating and environmental conditions, together with procedures formodifying these rates to reflect actual on-road operating conditions. Measured emission rates differ among types of vehicles (passengerautomobiles, light and heavy-duty trucks, and motorcycles), as well asby model year and age, reflecting changes in new-vehicle emissionstandards and the increase in emission rates that typically occurswith accumulated mileage. The MOBILE model uses measured emissionrates from a sample of vehicles run through the Federal Test Procedure(FTP).Actual per-vehicle mile emission rates are calculated by adjustingthese basic emission rates to reflect differences between the test andactual conditions. These differences include tampering with emissionscontrol equipment, variation in driving patterns from those used tomeasure emissions rates, and air temperatures different from that (75degrees) at which emissions testing is conducted. Applying theappropriate correction factors to the basic emission rate produces anestimate of its actual exhaust emissions rate in urban driving. Finally, evaporative hydrocarbon emissions from vehicles' fuel systemsare added to these tailpipe emission rates to determine totalemissions per mile of operation. The resulting total emission factorsare supplemented with information on the age distribution andutilization of each type of vehicle to estimate the average emissionsper mile of each pollutant generated by the total number of suchvehicles operating in the urban area. Total vehicle emissions are estimated by applying the per-mile vehiclerates (from emissions models) to estimates of VMT. Separatecontributions to total vehicle emissions can be estimated fordifferent time periods of the day, vehicle types, and transportationfacilities.. (tranchal.html)